نتایج جستجو برای: antiferromagnetism
تعداد نتایج: 4003 فیلتر نتایج به سال:
We show that there is a thermoinduced contribution to the magnetic moment of nanoparticles of antiferromagnetic materials. It arises from thermal excitations of the uniform spin-precession mode, and it has the unusual property that its magnitude increases with increasing temperature. This has the consequence that antiferromagnetism is nonexistent in nanoparticles at finite temperatures and it e...
We have studied the two-dimensional S=1/2 square-lattice antiferromagnet Cu(pz)_{2}(ClO4)_{2} (where pz denotes pyrazine), using neutron inelastic scattering and series expansion calculations. We show that the presence of antiferromagnetic next-nearest-neighbor interactions enhances quantum fluctuations associated with resonating valence bonds. Intermediate magnetic fields lead to a selective t...
Two isostructural 1D compounds {[M3(hpdc)2(H2O)6] 2H2O}n (M = Mn, Co; H3hpde = 2-hydroxypyrimidine-4,6-dicarboxylic acid) were synthesized by the in situ hydrothermal reactions of 2-chloropyrimidine-4,6-dicarboxylic acid with MCl2 (M = Mn, Co) and NaOH; the MnII compound shows spin-canted antiferromagnetism, whereas the CoII compound exhibits the coexistence of spin-canting and a two-step field...
The magnetism of the t − t ′ Hubbard model Abstract The magnetic properties of the t − t ′ Hubbard model in the two dimensional square lattice are studied within an unrestricted Hartree Fock approximation in real space. The interplay between antiferromagnetism, ferromagnetism, phase separation and in-homogeneous magnetic textures is studied. It is shown that, at sufficiently large values of t ′...
....................................................................................................................................... ix Chapter 1: Introduction ........................................................................................................ 1 1.1 General Introduction ........................................................................................... 1 1.2 Moti...
The interplay between doping and antiferromagnetism is a central issue in theories of the oxide superconductors. Undoped La2Cu04 is known to be an antiferromagnetic insulator, and may be modeled by Cu02 planes with a spin2 local moment on each Cu. Sr doping introduces holes into the oxygen p orbitals. Following Anderson's suggestion, ' there has been considerable interest in the "t-J"model of a...
Laboratory for Quantum Magnetism, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen, Switzerland Helmholtz-Zentrum Berlin, 14109 Berlin Wannsee, Germany James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA London Centre for Nanotechnology and Department...
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