and is usually lower than the N el temperature. Other properties Antiferromagnetism plays a crucial ... to antiferromagnetism. Sergei Tyablikov Tyablikov S.V 1995 Methods in the Quantum Theory of Magnetism ... sk Antiferomagnetizmus fi Antiferromagnetismi sv Antiferromagnetism tr Antiferrom knat sl k uk ... more details
Unreferenced stub auto yes date December 2009 Helimagnetism is an incommensurate form of magnetic ordering that results from the competition between Ferromagnetic and Antiferromagnetic exchange interactions, and is typically only observed at liquid helium temperatures. Spins of neighbouring magnetic moments arrange themselves in a spiral or helical pattern, with a characteristic turn angle of somewhere between 0 and 180 degrees. It is possible to view Ferromagnetism and Antiferromagnetism as Helimagnetic structures with characteristic turn angles of 0 and 180 degrees respectively. Helimagnetic order breaks spatial inversion symmetry, as it can be either left handed or right handed in nature. magnetic states Category Magnetism Condensedmatter stub fr H limagn tisme ... more details
The Morin transition is a magnetic phase transition in Fe sub 2 sub O sub 3 sub hematite where the antiferromagnetic ordering is reorganized from being aligned perpendicular to the c axis to be aligned parallel to the c axis below T sub M sub . T sub M sub 260K for Fe sup 3 sup in Fe sub 2 sub O sub 3 sub . A change in magnetic properties takes place at the Morin transition temperature. See also Ferromagnetism Antiferromagnetism Paramagnetism N el temperature References http flux.aps.org meetings YR00 MAR00 abs S240005.html American Physical Society abstract br Category Magnetism sl Morinov prehod ... more details
KCUF may refer to KGHT , a radio station 100.5 FM licensed to El Jebel, Colorado, United States, which held the call sign KCUF from August 2005 to June 2010 The call sign of a fictional radio station located in the equally fictional Kinneret, California in Thomas Pynchon s The Crying of Lot 49 In The Illuminatus Trilogy , Knights of Christianity United in Faith , likely as an homage to Pynchon s usage A number of internet radio stations call themselves KCUF A Punk rock punk band is named KCUF Potassium trifluorocuprate, KCuF sub 3 sub , is an antiferromagnetism antiferromagnetic perovskite structure perovskite in which unconfined spinon s have been observed http prola.aps.org abstract PRL v70 i25 p4003 1 disambig callsign ... more details
chembox verifiedrevid 367493807 Name Terbium silicide ImageFile ImageSize ImageName Terbium silicide IUPACName Terbium silicide OtherNames Terbium silicon br Silicon terbium br Terbium Disilicide Section1 Chembox Identifiers CASNo Section2 Chembox Properties Formula TbSi sub 2 sub MolarMass 215.09 g mol Appearance Gray powder Density Solubility Insoluble MeltingPt BoilingPt Section3 Chembox Structure MolShape Coordination CrystalStruct Orthorhombic or Hexagonal Dipole Section7 Chembox Hazards ExternalMSDS MainHazards Section8 Chembox Related OtherAnions OtherCations OtherCpds Rare Earth Silicides Terbium silicide is a chemical compound of the rare earth metal terbium with silicon having chemical formula TbSi sub 2 sub . It is a gray solid first described in detail in the late 1950 s. ref name Perri1959 cite doi 10.1021 j150574a041 ref The metallic resistivity and low Schottky barrier of TbSi sub 2 sub on N type semiconductor n type doped silicon make it a potential candidate for applications such as infrared detector s, ohmic contact s, Magnetoresistive Random Access Memory magnetoresistive devices , and Thermoelectric Devices and Materials thermoelectric devices . It exhibits antiferromagnetism at 16K. ref name Sekizawa1966 Cite journal author Sekizawa, K. Yasukochi, K. year 1966 title Antiferromagnetism of disilicides of heavy rare earth metals journal Journal of the Physical Society of Japan. volume 21 issue 2 pages 274 278 doi 10.1143 JPSJ.21.274 bibcode 1966JPSJ...21..274S postscript None ref References reflist Terbium compounds Category Silicides Category Terbium compounds ... more details
File Bethe Slater curve by Zureks.svg thumb Bethe Slater curve elements above the horizontal axis are ferromagnetic, below the axis are antiferromagnetic Bethe Slater curve is a chart graphical representation of exchange energy for transition metals as a function of the ratio of the interatomic distance a to the radius r of the 3d electron shell . ref http www.nitt.edu home academics departments physics faculty lecturers justin students magnetic exchange ref The curve illustrates why certain metals are ferromagnetism ferromagnetic and other antiferromagnetism antiferromagnetic . For a pair of atoms, the exchange interaction w sub ij sub responsible for the energy E is calculated as ref Soshin Chikazumi, Physics of Ferromagnetism, Oxford University Press, New York, 1997, page 125, ISBN 0 19 851776 9 ref math w ij 2 cdot J cdot S i cdot S j math where J exchange integral, S electron spins, i and j indices of the two atoms. References reflist Category Magnetism de Bethe Slater Kurve pl Krzywa Bethe Slatera ... more details
and antiferromagnetism . In 1948 they developed a consistent theoretical polar model of metals ... important contribution to antiferromagnetism was in the development of the method of quantum ... more details
mergeto Mott insulator date May 2008 In condensed matter physics, mottness is a term which denotes the additional ingredient, aside from antiferromagnetic ordering, which is necessary to fully describe a Mott Insulator . In other words, we might write antiferromagnetic order mottness Mott insulator Thus, mottness accounts for all of the properties of Mott insulators that cannot be attributed simply to antiferromagnetism. Properties There are a number of properties of Mott insulators, derived from both experimental and theoretical observations, which cannot be attributed to antiferromagnetic ordering and thus constitute mottness. These properties include Spectral weight transfer on the Mott scale ref name Phillips ref name Meinders Vanishing of the single particle Green s function many body theory Green function along a connected surface in momentum space in the brillouin zone first brillouin zone ref name Stanescu Two sign changes of the Hall effect Hall coefficient as electron doping semiconductors doping goes from math n 0 math to math n 2 math Electronic band structure band insulators have only one sign change at math n 1 math The presence of a charge math 2e math with math e 0 math the charge of an electron boson at low energies ref name Leigh ref name Choy A pseudogap away from half filling math n 1 math ref name Stanescu2 See also Mott insulator Hubbard model Antiferromagnetism Green s function many body theory References R.B. Laughlin, A Critique of Two Metals, http arxiv.org abs cond mat 9709195 Philip W. Anderson and G. Baskaran, A Critique of A Critique of Two Metals, http arxiv.org abs cond mat 9711197 references ref name Phillips Philip Phillips, Mottness, http arxiv.org abs cond mat 0702348 ref ref name Meinders M.B.J. Meinders, H. Eskes, and G.A. Sawatzky, Phys. Rev. B 48 3916 1993 ref ref name Stanescu Tudor D. Stanescu, Philip Phillips, and Ting Pong Choy, Theory of the Luttinger surface in doped Mott insulators, Phys. Rev. B 75 104503 2007 ref ref n ... more details
Use dmy dates date September 2010 Timeline of states of matter and phase transitions 1895 Pierre Curie discovers that induced magnetization is proportional to magnetic field strength 1911 Heike Kamerlingh Onnes discloses his research on superconductivity 1912 Peter Debye derives the T cubed law for the low temperature heat capacity of a nonmetallic solid 1925 Ernst Ising presents the solution to the one dimensional Ising model 1928 Felix Bloch applies quantum mechanics to electronic band structure electrons in crystal lattices , establishing the quantum theory of solids 1929 Paul Dirac Paul Adrien Maurice Dirac and Werner Karl Heisenberg develop the quantum theory of ferromagnetism 1932 Louis N el Louis Eug ne F lix Neel discovers antiferromagnetism 1933 Walter Meissner and Robert Ochsenfeld discover perfect superconducting diamagnetism 1933 1937 Lev Davidovich Landau develops the Landau theory of phase transition s 1937 Pyotr Leonidovich Kapitsa and John Frank Allen discover superfluid ity 1941 Lev Davidovich Landau explains superfluid ity 1942 Hannes Alfven predicts magnetohydrodynamics magnetohydrodynamic waves in plasmas 1944 Lars Onsager publishes the exact solution to the two dimensional Ising model 1957 John Bardeen , Leon Cooper , and Robert Schrieffer develop the BCS theory of superconductivity End of the 50s Lev Davidovich Landau develops the theory of Fermi liquid 1959 Philip Warren Anderson predicts Anderson localization localization in disordered systems 1972 Douglas Osheroff , Robert Coleman Richardson Robert C. Richardson , and David Lee physicist David Lee discover that helium 3 can become a superfluid 1974 Kenneth G. Wilson develops the renormalization group technique for treating phase transitions 1980 Klaus von Klitzing discovers the quantum Hall effect 1982 Horst L. Stoermer and Daniel C. Tsui discover the fractional quantum Hall effect 1983 Robert B. Laughlin explains the fractional quantum Hall effect 1987 Karl Alexander M ller and Georg Bednor ... more details
AFM may refer to TOC right Organizations Africa Fighting Malaria , a health campaign in Africa Alex von Falkenhausen Motorenbau , a German racing car constructor American Federation of Motorcyclists , a road racing club in the United States American Federation of Musicians , a labor union of musicians in North America American Film Market , an annual event for the financing of film production and distribution American Freedom Mortgage, Inc. , a corporation based in Georgia, U.S. Autoriteit Financi le Markten , Netherlands financial markets regulator Macau Football Association , the governing body of football in Macau Armed Forces of Malta , the name given to the combined armed services of Malta Acronym http www.asfmra.org AFM Accredited Farm Manager, Designated Farm Manager Member of the American Society of Farm Managers and Rural Appraisers , a degree requiring ascending levels of tests and education. Publications Aquarium Fish Magazine , a North American monthly magazine Annals of the Four Masters , a chronicle of medieval Irish history Science and technology AFM gene , in biochemistry, a member of the albumin gene family that encodes the protein Afamin Abrasive Flow Machining , a technique for smoothing internal part surfaces Adobe Font Metrics , a computer file format Air flow meter , a device that measures how much air is flowing through a tube AFm phase , or Alumina, Ferric oxide, monosulfate phase, in chemistry Antiferromagnetism , a material property and type of magnetic ordering Atomic force microscope , a high resolution type of scanning probe microscope Audio Frequency Modulation , an audio recording standard Military Air Force Medal , awarded in the Royal Air Force United Kingdom United States Air Force Memorial , in Arlington, Virginia Music AFM Records disambig de AFM fr AFM it AFM nl AFM ja AFM no AFM pl AFM pt AFM fi AFM ... more details
The Heisenberg model is the math n 3 math case of the n vector model , one of the models used in statistical physics to model ferromagnetism , and other phenomena. It can be formulated as follows take a d dimensional lattice group lattice , and a set of spins of the unit length math vec s i in mathbb R 3, vec s i 1 quad 1 math , each one placed on a lattice node. The model is defined through the following Hamiltonian mechanics Hamiltonian math mathcal H sum i,j mathcal J ij vec s i cdot vec s j quad 2 math with math mathcal J ij begin cases J & mbox if i, j mbox are neighbors 0 & mbox else. end cases math a coupling between spins. The general mathematical formalism used to describe and solve the Heisenberg model and certain generalizations is developed in the article on the Potts model . Note that in the continuum limit the Heisenberg model 2 gives the following equation of motion math vec S t vec S wedge vec S xx . quad 3 math This equation is called the continuous classical Heisenberg ferromagnet equation or shortly Heisenberg model and is integrable in the soliton sense. It admits several integrable and nonintegrable generalizations like Landau Lifshitz equation , Ishimori equation and so on. See also Heisenberg model quantum Ising model XY model Magnetism Ferromagnetism Landau Lifshitz equation Ishimori equation External links http prola.aps.org abstract PRL v17 i22 p1133 1 Absence of Ferromagnetism or Antiferromagnetism in One or Two Dimensional Isotropic Heisenberg Models http www.math.ucdavis.edu bxn qs.html The Heisenberg Model a Bibliography physics stub Category Magnetism Category Spin models Category Condensed matter physics Category Lattice models ja ... more details
DISPLAYTITLE 5 Dehydro m xylylene chembox Name 5 Dehydro m xylylene ImageFile DMX line.png ImageSize 150px ImageName 5 Dehydro m xylylene IUPACName 5 dehydro 1,3 quinodimethane OtherNames 5 dehydro m xylylene, br DMX Section1 Chembox Identifiers CASNo 681440 83 5 Section2 Chembox Properties Formula C sub 8 sub H sub 7 MolarMass 103.14 g mol 5 Dehydro m xylylene DMX is an aromaticity aromatic organic chemistry organic free radical triradical and the first known organic molecule to violate Hund s rule of maximum multiplicity Hund s Rule . ref cite journal author L Slipchenko et al. title 5 Dehydro 1,3 quinodimethane A Hydrocarbon with an Open Shell Doublet Ground State journal Angewandte Chemie International Edition year 2004 volume 43 pages 742 doi 10.1002 anie.200352990 pmid 14755709 issue 6 ref Its electronic ground state is an open shell open shell doublet rather than a quartet that is, it contains three low Spin physics spin coupled unpaired electrons in three singly occupied molecular orbital s. Because there are radical electrons in both spin states, this compound is said to exhibit antiferromagnetism . Though similar ground states are observed in molecules containing transition metal atoms, it is unprecedented in organic molecules. The 5 dehydro m xylylene anion DMX sup sup has also been studied extensively. It has a triplet ground state consisting of a phenyl anion and a m xylylene biradical . References references External links http physicsweb.org articles news 8 2 5 Physics web Radical molecule breaks the rules http www.chem.purdue.edu NewsFeed newsstory.asp?itemID 94 Purdue University Department of Chemistry Rule breaking molecule http www rcf.usc.edu krylov Publications PDFs CEN dmx.html Triradical breaks the rules http www.usc.edu schools college college magazine may 2004 krylov.html A discovery that breaks the laws of chemistry http www.compchemwiki.org index.php?title 5 dehydro m xylylene Computational Chemistry Wiki DEFAULTSORT Dehydro m xylylene, 5 ... more details
In statistical physics , the anisotropic or axial next nearest neighbor ising model , usually known as the ANNNI model , is a variant of the Ising model in which competing ferromagnetism ferromagnetic and antiferromagnetism antiferromagnetic exchange interaction s couple spin physics spins at nearest and next nearest neighbor sites along one of the crystallographic axes of the Bravais lattice lattice . The model is a prototype for complicated spatially modulated magnetic superstructure s in crystal s. The model was introduced in 1961 by Roger Elliott physicist Roger Elliott from the University of Oxford , but only given this name in 1980 by Michael E. Fisher and Walter Selke . It provides a theoretical basis for understanding numerous experimental observations on commensurability mathematics commensurate and commensurability mathematics incommensurate structures, as well as accompanying phase transition s, in magnet s, alloy s, adsorbate s, and other solid s. References cite journal author R. J. Elliott authorlink Roger Elliott physicist date 1961 title Phenomenological discussion of magnetic ordering in the heavy rare earth metals journal Phys. Rev. volume 124 pages 346&ndash 353 doi 10.1103 PhysRev.124.346 cite journal author Michael E. Fisher M.E. Fisher and Walter Selke W. Selke date 1980 title Infinitely many commensurate phases in a simple Ising model journal Phys. Rev. Lett. volume 44 pages 1502&ndash 1505 doi 10.1103 PhysRevLett.44.1502 cite journal author Per Bak P. Bak date 1982 title Commensurate phases, incommensurate phases, and the devil s staircase journal Reports on Progress in Physics volume 45 pages 587&ndash 629 doi 10.1088 0034 4885 45 6 001 cite journal author Walter Selke W. Selke date 1988 title The ANNNI model Theoretical analysis and experimental application journal Physics Reports volume 170 pages 213&ndash 264 doi 10.1016 0370 1573 88 90140 8 Category statistical mechanics Category Lattice models de ANNNI Modell it Modello ANNNI ... more details
Antiferroelectricity is a physical property of certain materials. It is closely related to ferroelectricity the relation between antiferroelectricity and ferroelectricity is analogous to the relation between antiferromagnetism and ferromagnetism . An antiferroelectric material consists of an ordered crystal line array of electric dipole s from the ions and electrons in the material , but with adjacent dipoles oriented in opposite antiparallel directions the dipoles of each orientation form interpenetrating sublattices, loosely analogous to a checkerboard pattern . ref http www.iupac.org goldbook F02347.pdf IUPAC goldbook ref ref C. Kittel, Theory of Antiferroelectric Crystals , Phys. Rev. 82, 729 732 1951 . http dx.doi.org 10.1103 PhysRev.82.729 DOI web link ref This can be contrasted with a ferroelectric, in which the dipoles all point in the same direction. In an antiferroelectric, unlike a ferroelectric, the total, macroscopic polarization density spontaneous polarization is zero, since the adjacent dipoles cancel each other out. Antiferroelectricity is a phase matter phase of a material, and it can appear or disappear more generally, strengthen or weaken depending on temperature, pressure, external electric field, growth method, and other parameters. In particular, at a high enough temperature, antiferroelectricity disappears this temperature is called the antiferroelectric Curie point . ref See, for example, C. Pulvari, Ferrielectricity, Phys. Rev. 120, 1670 1673 1960 http dx.doi.org 10.1103 PhysRev.120.1670 DOI web link ref References reflist Polarization states material stub Category Condensed matter physics Category Electrical phenomena fr Antiferro lectricit ... more details
Herbert Wagner born 6 April 1935 is a German theoretical physicist, who mainly works in statistical mechanics . He is a professor emeritus of Ludwig Maximilian University of Munich . TOC Biography Wagner was one of the last students of German theoretical physicist and Nobel prize winner Werner Heisenberg , with whom he worked on magnetism. ref W. Heisenberg, H. Wagner, K. Yamazaki Magnons in a model with antiferromagnetic properties , Il Nuovo Cimento 59, 377 391 1969 , DOI 10.1007 BF02755024. ref As a postdoc at Cornell University , he and David Mermin and independently of Pierre Hohenberg proved a no go theorem , otherwise known as the Mermin Wagner theorem . The theorem states that continuous symmetries cannot be spontaneous symmetry breaking spontaneously broken at finite temperature in systems with sufficiently short range interactions in dimensions math d le 2 math . ref N.D. Mermin, H. Wagner Absence of Ferromagnetism or Antiferromagnetism in One or Two Dimensional Isotropic Heisenberg Models , Phys. Rev. Lett. 17, 1133 1136 1966 . ref Wagner is the academic father of a generation of statistical physicists. Many of his students and junior collaborators now occupy chairs in German universities, including Hans Werner Diehl Essen , Siegfried Dietrich Wuppertal, then Stuttgart , Klaus Mecke Erlangen , Reinhard Lipowsky Max Planck Institute of Colloids and Interfaces, Berlin , Hartmut L wen D sseldorf and Udo Seifert Stuttgart . Awards In 1992, Wagner was awarded an honorary degree by the University of Essen now University of Duisburg Essen . ref http www.theo phys.uni essen.de tp Ehrenpromotionen.html Ehrenpromotionen in der Theoretischen Physik an der Universit t & 91 Duisburg & 93 Essen ref References reflist Persondata Metadata see Wikipedia Persondata . NAME Wagner, Herbert ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH 6 April 1935 PLACE OF BIRTH DATE OF DEATH PLACE OF DEATH DEFAULTSORT Wagner, Herbert Category German physicists Category 1935 births Categ ... more details
Not to be confused with Ferromagnetism for an overview see Magnetism Image Ferrimagnetic ordering.svg thumb Ferrimagnetic ordering In physics , a ferrimagnetic material is one in which the magnetic moment s of the atoms on different sublattice s are opposed, as in antiferromagnetism however, in ferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains. This happens when the sublattices consist of different materials or ion s such as Fe sup 2 sup and Fe sup 3 sup . Ferrimagnetism is exhibited by Ferrite magnet ferrite s and magnetic garnets. The oldest known magnetic substance, magnetite iron II,III oxide Iron Fe sub 3 sub Oxygen O sub 4 sub , is a ferrimagnet it was originally classified as a ferromagnet before Louis N el N el s discovery of ferrimagnetism and antiferromagnetism in 1948 . ref L. N el, Propri t es magn tiques des ferrites F rrimagn tisme et antiferromagn tisme , Annales de Physique Paris 3, 137 198 1948 . ref Some ferrimagnetic materials are YIG yttrium iron garnet and ferrites composed of iron oxide s and other elements such as aluminum , cobalt , nickel , manganese and zinc . Effects of temperature Image Ferrimagnetism magnetic moment as a function of temperature.svg thumb right 185px Below the magnetization compensation point, ferrimagnetic material is magnetic. At the compensation point, the magnetic components cancel each other and the total magnetic moment is zero. Above the Curie temperature Curie point , material loses magnetism. Ferrimagnetic materials are like ferromagnetism ferromagnets in that they hold a spontaneous magnetization below the Curie temperature , and show no magnetic order are paramagnetic above this temperature. However, there is sometimes a temperature below the Curie temperature at which the two sublattices have equal moments, resulting in a net magnetic moment of zero this is called the magnetization compensation point . This compensation point is observed easily in garnet s and ra ... more details
expert subject physics date March 2009 In physics, the term clusters denotes small, multiatom particles. As a rule of thumb, any particle of somewhere between 3 and 3x10 sup 7 sup atom s is considered a cluster. Two atom particles are sometimes considered clusters as well Fact date February 2007 . The term can also refer to the organization of protons and neutrons within nuclein. Although first reports of cluster species date back already to the 1940s ref name hahn cite journal author Mattauch J, Ewald H, Hahn O, Strassmann F. title Hat ein Caesum Isotop langer Halbwertszeit existiert? Ein Beitrag zur Deutung ungew hnlicher Linien in der Massenspektrographie journal Zeitschrift f r Physik volume 120 pages 598 617 year 1943 ref , Cluster science emerged as a separate direction of research in the 1980s, One purpose of the research was to study the gradual development of collective phenomena which characterize a bulk solid. These are for example the color of a body, its electrical conductivity, its ability to absorb or reflect light, and magnetic phenomena such as ferro , ferri , or antiferromagnetism. These are typical collective phenomena which only develop in an aggregate of a large number of atoms. It was found that collective phenomena break down for very small cluster sizes. It turned out, for example, that small clusters of a ferromagnetic material are super paramagnetic rather than ferromagnetic. Paramagnetism is not a collective phenomenon, which means that the ferromagnetism of the macrostate was not conserved by going into the nanostate. The question then was asked for example How many atoms do we need in order to obtain the collective metallic or magnetic properties of a solid ? Soon after the first cluster sources had been developed in 1980, an ever larger community of cluster scientists was involved in such studies. This development led to the discovery of fullerenes in 1986 and carbon nanotubes a few years later. In science, a lot is known about properti ... more details
The term magnetic structure of a material pertains to the ordered arrangement of magnetic spins, typically within an ordered crystallographic lattice . Its study is a branch of solid state chemistry . Image Antiferromagnetic ordering.svg thumb 200px A very simple antiferromagnetic structure the magnetic structure are the things which is related to the metal Techniques to study them Such ordering can be studied by observing the magnetic susceptibility as a function of temperature and or the size of the applied magnetic field, but a truly three dimensional picture of the arrangement of the spins is best obtained by means of neutron diffraction ref Neutron diffraction of magnetic materials Yu. A. Izyumov, V.E. Naish, and R.P. Ozerov translated from Russian by Joachim B chner. New York Consultants Bureau, c1991.ISBN 030611030X ref ref http www.aps.anl.gov Xray Science Division Powder Diffraction Crystallography 2006ACNSmagnetGSAS YBAFEOexampleMovie YBAFEOexample.html A demonstration by Brian Toby ref . Neutrons are primarily scattered by the nuclei of the atoms in the structure. At a temperature above the ordering point of the magnetic moments, where the material behaves as a paramagnetic one, neutron diffraction will therefore give a picture of the crystallographic structure only. Below the ordering point, e.g. the N el temperature of an antiferromagnetism antiferromagnet of the Curie temperature Curie point of a ferromagnet the neutrons will also experience scattering from the magnetic moments because they themselves possess spin. The intensities of the Bragg reflection s will therefore change. In fact in some cases entirely new Bragg reflections will occur if the unit cell of the ordering is larger than that of the crystallographic structure. Thus the symmetry of the total structure may well differ from the crystallographic substructure. It needs to be described by one of the 1651 magnetic Shubnikov groups ref p.428 Group Theoretical Methods and Applications to Molec ... more details
Image Shubnikv.JPG right 250px thumb Lev Shubnikov Lev Vasilyevich Shubnikov lang ru lang uk September 9, 1901&mdash November 10, 1937 was a USSR Soviet experimental physicist who worked in the Netherlands and USSR . Shubnikov was born into the family of a Saint Petersburg accountant. After graduating from a Gymnasium school gymnasium he entered Saint Petersburg State University Leningrad University . This was the first year of the Russian Civil War and he was the only student of that year attending the physics department. While yachting in the Gulf of Finland in 1921, he accidentally sailed from Saint Petersburg to Finland , was sent to Germany and could not return to Russia until 1922. He then continued his education in the Leningrad Polytechnical Institute , graduating in 1926. During his university training he worked with Ivan Obreimov , developing a new method for growing monocrystal s of metals. In 1926, at the recommendation of Abram Ioffe , he was sent to the Leiden cryogenic laboratory of Wander Johannes de Haas in the Netherlands he worked there until 1930. Shubnikov studied bismuth crystals with low impurity concentrations, and in cooperation with Wander Johannes de Haas he discovered magnetoresistance oscillations at low temperatures in magnetic field s the Shubnikov De Haas effect . The importance of this effect for condensed state physics became completely clear only much later. Today this effect is one of the principal instruments used in studying the quantum electron properties of solids. In 1930 Shubnikov returned to Kharkov and established there the first Soviet cryogenic laboratory. He also discovered the antiferromagnetism in 1935 and paramagnetism in 1936, together with Boris Lazarev of solid state hydrogen . He was one of the first to study liquid helium . In 1937, at the height of the Great Purge , the NKVD launched the UPTI Affair Ukrainian Physics and Technology Institute Affair on the basis ... more details
orphan date January 2011 Lattice density functional theory LDFT is a statistical theory used in physics and thermodynamics to model a variety of physical phenomena with simple Lattice model physics lattice equations. Lattice models with nearest neighbor interactions have been used extensively to model a wide variety of systems and phenomena, including the lattice gas, binary liquid solutions, order disorder phase transitions , ferromagnetism , and antiferromagnetism ref Hill TL. Statistical Mechanics, Principles and Selected Applications. New York Dover Publications 1987. ref . Most calculations of correlation functions for nonrandom configurations are based on statistical mechanical techniques, which lead to equations that usually need to be solved numerically. In 1925, Ising ref Ising E. Report on the theory of ferromagnetism. Zeitschrift Fur Physik, 31, 253 1925 . ref gave an exact solution to the one dimensional 1D lattice problem. In 1944 Onsager ref Onsager L. Crystal statistics I A two dimensional model with an order disorder transition. Physical Review, 65, 117 1944 . ref was able to get an exact solution to a two dimensional 2D lattice problem at the critical density. However, to date, no three dimensional 3D problem has had a solution that is both complete and exact ref Hill TL. An introduction to statistical thermodynamics, New York, Dover Publications 1986 . ref . Over the last ten years, Aranovich and Donohue have developed lattice density functional theory LDFT based on a generalization of the Ono Kondo equations to three dimensions, and used the theory to model a variety of physical phenomena. The theory starts by constructing an expression for free energy , A U TS, where internal energy U and entropy S can be calculated using mean field approximation. The grand potential is then constructed as A , where is a Lagrange multiplier which equals to the chemical potential , and is a constraint given by the lattice. It is then possible to minimize t ... more details
Infobox Scientist box width name Louis Eug ne F lix N el image filename only image size caption birth date Birth date 1904 11 22 df y birth place Lyon , France death date Death date and age 2000 11 17 1904 11 22 df y death place residence citizenship nationality ethnicity fields Solid state physics workplaces alma mater cole Normale Sup rieure doctoral advisor academic advisors doctoral students notable students known for author abbrev bot author abbrev zoo influences influenced awards Nobel Prize in Physics 1970 religion signature filename only footnotes Louis Eug ne F lix N el 22 November 1904 &ndash 17 November 2000 was a France French physicist born in Lyon . He studied at the Lyc e du Parc in Lyon and was accepted at the cole Normale Sup rieure in Paris . He was corecipient with the Sweden Swedish astrophysicist Hannes Alfv n of the Nobel Prize for Physics in 1970 for his pioneering studies of the magnetic properties of solid s. His contributions to solid state physics have found numerous useful applications, particularly in the development of improved computer memory units. About 1930 he suggested that a new form of magnetic behavior might exist called antiferromagnetism , as opposed to ferromagnetism . Above a certain temperature the N el temperature this behaviour stops. N el pointed out 1947 that materials could also exist showing ferrimagnetism . N el has also given an explanation of the weak magnetism of certain rocks, making possible the study of the history of Earth s magnetic field . Biography N el was born in Lyons on 22 November 1904. In 1931 he married H l ne Hourticq they have three children, Marie Fran oise, Attach e d Administration at the Conseil d Etat, Marguerite, married to Gu ly, Professeur agr g e d histoire, and Pierre, who is a television producer. Louis N el studied at the Ecole Normal Sup rieure in Paris from 1924 1928, where he was appointed lecturer in 1928. In 1932 he obtained the degree of Doctor of Science at the University of St ... more details
In chemistry a boride is a chemical compound between boron and a less electronegativity electronegative element. This is a very large group of compounds that are generally high melting and are not ionic in nature. Some borides exhibit very useful physical properties. The term boride is also loosely applied to compounds such as B sub 12 sub As sub 2 sub N.B. Arsenic has an electronegativity higher than boron that is often referred to as boron arsenide icosahedral boride . Ranges of compounds The borides can be classified loosely as boron rich or metal rich, for example the compound Yttrium borides YB sub 66 sub at one extreme through to Nd sub 2 sub Fe sub 14 sub B at the other. The generally accepted definition is that if the ratio of boron atoms to metal atoms is 4 1 or more the compound is boron rich, if it is less, then it is metal rich. Boron rich borides B M 4 1 or more The main group metals, lanthanide s and actinide s form a wide variety of boron rich borides, with metal boron ratios up to Yttrium borides YB sub 66 sub . The properties of this group vary from one compound to the next, and includes examples of compounds that are semi conductors, superconductors, diamagnetism diamagnetic , paramagnetism paramagnetic , ferromagnetism ferromagnetic or antiferromagnetism anti ferromagnetic . ref cite journal author Lundstrom T journal Pure & Applied Chem year 1985 volume 57 issue 10 page 1383 title Structure, defects and properties of some refractory borides format free download pdf doi 10.1351 pac198557101383 ref They are mostly stable and refractory. Some metallic dodecaborides contain boron icosahedra, others for example yttrium , zirconium and uranium have the boron atoms arranged in cuboctahedron cuboctahedra . ref cite journal last Matkovich first V.I. coauthors J Economy, R F Giese Jr, R Barrett year 1965 title The structure of metallic dodecaborides journal Acta Cryst. volume 19 pages 1056 1058 url http journals.iucr.org q issues 1965 12 00 a04941 a04941.p ... more details
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