Magnetic properties and exchange interactions in TbNi(5-x)M(x) (M=Co and Fe) compounds: Ab initio calculations

Abstract

In order to investigate magnetic structure and the mechanism of the Curie temperature (T(C)) enhancement in TbNi(4)Co and TbNi(4)Fe compounds in comparison with TbNi(5), electronic structure calculations were performed within the LSDA + U method (local spin density approximation with Hubbard U-correction). Magnetic moments for Ni, Fe, and Tb ions resulted from the LSDA + U calculations for TbNi(5) and TbNi(4)Fe compounds were found to be in very good agreement with the ones refined from the neutron data. Experimental magnetization measurements demonstrate a substantial increase of T(C) in TbNi(4)Co (T(C) similar to 60 K) and especially in TbNi(4)Fe (T(C) similar to 280 K) in comparison with TbNi(5) (T(C) similar to 23 K) that correlates with the growth of the exchange-interaction parameter in the 3d sublattice calculated in the present work. (C) 2011 American Institute of Physics. [doi:10.1063/1.3563083]