High field magnetization of R2Fe14B compounds measured up to 55 T

Magnetic field induced spin reorientation was studied in R2Fe14B (R = Nd, Tm and Er) single crystals up to 55 T under pulsed high magnetic fields and also up to to 23 T by means of a hybrid magnet. A dual coil system for the pulse magnet was developed for measuring the magnetization process with an initial steep increase accurately by an induction method. A brand-new mechanical system was developed for the magnetization measurement in the hybrid magnet using an extraction method. The magnetization processes of multiple samples were measured simultaneously in one generation of the magnetic field. The incipient stage of the transition from ferri-to ferromagnetism was clearly observed in the magnetization curve along the [100] and [110] directions in Er2Fe14B and Tm2Fe14B crystals. The transition fields were roughly estimated to be 70 T and 55 T along the [100] direction for Er and Tm compounds, respectively. The forced spin reorientation transition was measured in Nd2Fe14B crystal along the [100] direction at various temperatures. A steep increase of magnetization appeared at 200 K with decreasing temperature. The magnetization processes were also measured along several directions within the c-plane. When the field direction approached [110], the distinct transition diminished.