Magnetic properties of RFe 6Ga 6 compounds (R=Gd, Dy, Ho, Er, Tm)

Abstract

We have studied the magnetic properties of several ternary rare-earth compounds of the composition RFe 6Ga 6 (R=Gd, Dy, Ho, Er, Tm) by means of magnetization measurements in high fields up to 35 T. All these compounds cystallize in the tetragonal ThMn 12 type of structure. This structure has three non-rare-earth sites. Previous neutron-diffraction studies have shown that the Fe and Ga atoms preferentially occupy the 8f and 8 i sites, respectively. These two types of atoms share the 8 j site. The RFe 6Ga 6 compounds have magnetic ordering temperatures somewhat above 500 K. At 4.2 K, the net magnetization is fairly small because of the mutually compensating effect of the R- and Fe-sublattice magnetizations. Under these circumstances, the high-field free powder method, used by us previously, offers the possibility to study the intersublattice magnetic coupling in these materials. For all five compounds investigated, we have determined experimental values of the intersublattice-coupling constants. Our results are discussed in terms of the systematics derived previously for the behaviour of the intersublattice-coupling strength in a variety of different types of R–Fe intermetallics.