High-field magnetization measurements on Er₂Fe₁₇ single crystals

If the easy magnetization direction of a 3d-4f ferrimagnet is perpendicular to a high-symmetry axis, a magnetic field applied in the easy direction may induce a number of first-order transitions, the first (lowest-field) one of which carries the information sufficient for an unambiguous determination of the intersublattice molecular field. This idea has been used to find the molecular field in Er₂Fe₁₇. To this end, magnetization curves have been measured in pulsed magnetic fields of up to 50 T applied along [100] or [001]. In order to obtain a reference value of the molecular field by a conventional method, high-field measurements have also been performed on crystals free to rotate. The molecular fields determined by both techniques are in good agreement with each other as well as with the values deduced from literature data.