Recent neutron scattering experiments have shown that the low-temperature magnetic structures of most uranium pnictides are of the multiple-k⃗ type. In order to describe these, we use a simple model Hamiltonian consisting of an anisotropic exchange interaction between nearest- and next-nearest-neighbor ions and a crystal-field term. We show that the exchange determines the type (AFM-I, IA) and the polarization of the magnetic structure. Single- and multiple-k⃗ structures have the same exchange energy, though the spins are aligned along different high-symmetry directions: The crystal field determines which of these spin structures has the lowest energy. This model provides an explanation for the antiferromagnetic type-I structure of UN, UP, and USb and the type-IA structure of UAs, as well as for the possible number of k⃗ components
Low Temperature Magnetic structures in uranium monopnictides
MONACHESI, Patrizia;
1983-01-01
Abstract
Recent neutron scattering experiments have shown that the low-temperature magnetic structures of most uranium pnictides are of the multiple-k⃗ type. In order to describe these, we use a simple model Hamiltonian consisting of an anisotropic exchange interaction between nearest- and next-nearest-neighbor ions and a crystal-field term. We show that the exchange determines the type (AFM-I, IA) and the polarization of the magnetic structure. Single- and multiple-k⃗ structures have the same exchange energy, though the spins are aligned along different high-symmetry directions: The crystal field determines which of these spin structures has the lowest energy. This model provides an explanation for the antiferromagnetic type-I structure of UN, UP, and USb and the type-IA structure of UAs, as well as for the possible number of k⃗ componentsPubblicazioni consigliate
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