FULL MAGNETIZATION PROCESS OF 3D-4F HARD MAGNETIC-MATERIALS IN ULTRAHIGH MAGNETIC-FIELDS (AN EXAMPLE - RFE11TI)

The prospects of using the free-powder high-field magnetization method fora quantitative study of inter-sublattice exchange interaction in 3 d-4f hard magnetic materials an analyzed. Such analysis is stimulated by the availability of pulsed magnetic fields similar to 10(3) T gener ated by implosion. Particular attention is paid to effects due to magn etic anisotropy, essential for these materials. The 3d-4f ferrimagnets where both sublattices contribute positively to the easy-axis anisotr opy are shown to be suitable objects of study by the foe-powder method , because (i) anomalies in their low-temperature magnetizatization cur ves are sharp and (ii) anisotropic effects can be allowed for without quantitative knowledge of the anisotropy constants. Moreover, these '' good'' hard magnetic materials can be brought into metamagnetic regime by diluting the rare earth sublattice with nonmagnetic yttrium; then, regardless of the anisotropy constants, the magnetization curve at lo w temperatures has just one steplike anomaly, the threshold field bein g equal exactly to the molecular field acting on the rare earth. (C) 1 998 American Institute of Physics.