Pressure dependence of the magnetisation of YFe₂and ZrFe₂: computation and experiment

Values of delta ln sigma / delta P, where sigma is the magnetisation per unit mass, for YFe 2 (ZrFe 2 ) of -8.4+or-0.4 (-6.3+or-0.3)*10 -4 kbar -1 were obtained from forced magnetostriction measurements on polycrystalline samples at 4.2K in fields of up to 12 T. These values are shown to be in reasonable agreement with ab initio computer calculations of delta ln sigma / delta P but contradict earlier experimental work. The agreement between experiment and theory for delta ln sigma / delta P provides further evidence that YFe 2 and ZrFe 2 are ferrimagnetic.