Compton scattering studies of the temperature dependence of the spin moment inHoFe2

Compton scattering studies, performed at the KEK accumulation ring in Japan with circularly polarized synchrotron radiation, have been used to determine the spin-dependent Compton profile of ${\mathrm{HoFe}}_2$ at temperatures between 10 and 300 K. The holmium spin moment, which is antiferromagnetically coupled to that on the Fe sites, softens as the temperature rises leading to a reversal of the net spin direciton. This has been observed directly and the spin compensation temperature has been estimated from the Compton data to be 210±10 K.