ULTRAHIGH FIELD MAGNETIZATION OF YCO3 HYDRIDES

Magnetization measurements have been made for YCo3H(x) hydrides with x = 1.0 (beta1 hydride), 1.8 (beta2), 3.4 (gamma) and 4.0 (gamma) in magnetic fields up to 130 T at 4.2 K, and for the beta2 hydride up to 40 T between 4.2 and 160 K. The beta1 and gamma hydrides are antiferromagnetic and exhibit a field-induced spin-flip transition to a ferromagnet. The beta2 hydride is intermediately saturated ferromagnetic and transits to the saturated ferromagnetic state with two successive itinerant metamagnetic transitions like YCo3. Almost the same value of the Co moment is obtained in the saturated ferromagnetic state.