Magnetic properties of GdCo12B6 compound under high pressures

Abstract

The effects of hydrostatic pressure up to 10kbar on Curie temperature TC, compensation temperature TCOMP and spontaneous magnetization MS of ferrimagnetic GdCo12B6 compound have been studied. Two antiferromagnetically coupled sublattices that are carrying magnetization of typically 0.42μB/Co atom and 7μB/Gd cancel out at compensation temperature at about 50K and magnetic ordering temperature TC=163±2K. The volume dependence of intrinsic magnetic properties of the GdCo12B6 compound has been determined by studying it under hydrostatic pressure. The observed increase of MS with pressure (dMS/dp=+0.005 μBkbar−1 at 5K) is attributed predominantly to the pressure induced decrease of Co magnetic moments. The crucial role of Co in this behavior is confirmed by the change of sign of the pressure slope at temperatures above TCOMP and by the fact that the estimated decrease of mCo is also quite comparable with pressure induced decrease of MS in YCo12B6 (dMS/dp=−0.007μBkbar−1). The decrease of mCo is also responsible for the increase of TCOMP with pressure (dTCOMP/dp=+0.06Kkbar−1). The decrease of TC with pressure (dTC/dp=−0.55Kkbar−1) is comparable to the decrease observed on RCo12B6 compounds with non-magnetic R and can be attributed to the volume dependence of Co–Co exchange interactions. The remarkable role of the hybridization as a consequence of small distances between Co and B atoms could be a background of this rather unexpected volume stability of magnetic properties.