Journal of Applied Physics · 1964 · 56 citations · 2 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMagnetic MaterialsSolid State PhysicsCrystal LatticeCrystallographyFerrimagnetic MaterialsFerromagnetismMagnetic Properties Of SolidsNeutron DiffractionDiffraction PatternsFerrimagnetic OxidesLaves PhasesMagnetic Sublattice StructurePowder Neutron DiffractionSpinel OxidesSpinel StructureSpiral Magnetism
TbMn2 crystallizes with the cubic Laves-phase structure (C15-type) which may be regarded as the spinel structure without the anions. The ``A'' sites are occupied by Tb ions and the ``B'' sites by Mn ions. Neutron diffraction powder patterns run at 4.2°K exhibit a number of extra reflections characteristic of a modulated magnetic structure. These additional reflections can be indexed on the basis of a spiral modulation propagated along [110] with a wavelength of 8.0 Å. The spiral axis is along [001]. The ``B'' sites are ordered in a manner which is entirely analogous to the low-temperature ordering of Fe3O4; the two sublattice spirals being 180° out of phase. The A sublattice is in phase with a particular one of the two B sublattices. The combination of the internally compensated B sites and the ferromagnetically coupled A sites leads to a ferrimagnetic spiral.
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