Symmetry analysis of the magnetic structures in TbIG and Tb:YIG at low temperature

摘要: Magnetic structures in TbIG and terbium-yttrium ferrite garnet Tb0.37Y2.63IG are revisited using Bertaut' representation analysis for the highest crystallographic subgroups of space group Ia d with wave vector k = 0. Powder neutron diffraction experiments performed only on combined single crystal magnetization measurements. Three field-induced phase transitions observed at 4.2 K high magnetic fields up to 150 kOe along direction while remain easy axis magnetization. New parameters previous Tb3+ double umbrella structure found 5 a modified model rhombohedral subgroup Rc . From magnetizations crystal, non collinear is evidenced The 'square pyramid' predicted both basis vectors tetragonal I41/acd based effective spin Hamiltonian anisotropic exchange tensors requirement gyGy below Ta 80 where earlier reorientation occur between T1 40 T2 140 K. monoclinic C2/c tentatively proposed low symmetry angular phases All results compared works.