Magnetic structure

About: Magnetic structure is a research topic. Over the lifetime, 10787 publications have been published within this topic receiving 207143 citations.

Magnetic structure of the kagomé lattice antiferromagnet potassium jarosite KFe 3 ( OH ) 6 ( S O 4 ) 2

Abstract: We have examined the magnetic structure of the kagom\'e lattice antiferromagnet potassium jarosite (K jarosite: ${\mathrm{KFe}}_{3}{(\mathrm{OH})}_{6}{(\mathrm{S}\mathrm{O}}_{4}{)}_{2})$ by means of powder neutron diffraction. Extremely high degeneracy of the ground states prevents the long-range magnetic ordering at any temperature and the $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ structure is predicted theoretically to be favored rather than the $q=0$ structure at $T=0$ in a kagom\'e lattice Heisenberg antiferromagnet. Nevertheless, K jarosite shows long-range magnetic ordering at 65 K and the ordered magnetic structure was found to be the $q=0$ structure. In addition, although the $q=0$ structure has two degenerated states of ``positive'' and ``negative'' chirality, the observed magnetic structure contains only elemental triangles of positive chirality. We found that a weak single-ion-type anisotropy is crucial for selecting the observed magnetic structure. The long-range magnetic ordering at finite temperature in the jarosite family of compounds can be ascribed to this anisotropy.

Calculated electronic and magnetic structure of the nitrides NiFe3N and PdFe3N.

Abstract: The electronic and magnetic structure of the antiperovskite-structure transition-metal nitrides ${\mathrm{NiFe}}_{3}$N and ${\mathrm{PdFe}}_{3}$N are calculated employing the augmented-spherical-wave method. From these calculations the binding character is found to be mainly covalent for the nitrogen-iron bonds and metallic between the iron and nickel atoms, as stated in the earlier literature. The magnetic structure exhibits itinerant moments for the iron atoms and more localized moments at the Ni (Pd) atoms. Effects of external pressure are studied by varying the lattice constant. Such calculations yield the pressure dependence of the magnetic moments and the hyperfine fields. The total energy is computed as a function of magnetic moment and volume, yielding total-energy surfaces, that provide the basis for a spin-fluctuation model at finite temperatures. The possibility of an Invar-like behavior is found.

Robustness of basal-plane antiferromagnetic order and the J(eff)=1/2 state in single-layer iridate spin-orbit Mott insulators.

Abstract: The magnetic structure and electronic ground state of the layered perovskite Ba(2)IrO(4) have been investigated using x-ray resonant magnetic scattering. Our results are compared with those for Sr(2)IrO(4), for which we provide supplementary data on its magnetic structure. We find that the dominant, long-range antiferromagnetic order is remarkably similar in the two compounds and that the electronic ground state in Ba(2)IrO(4), deduced from an investigation of the x-ray resonant magnetic scattering L(3)/L(2) intensity ratio, is consistent with a J(eff)=1/2 description. The robustness of these two key electronic properties to the considerable structural differences between the Ba and Sr analogues is discussed in terms of the enhanced role of the spin-orbit interaction in 5d transition metal oxides.