High magnetic field study of the Tm2Fe17 and Tm 2Fe17D3.2 compounds

A magnetization study of a Tm2Fe17 single crystal and aligned powder of the deuteride Tm2Fe17D3.2 has been carried out in steady (14 T) and pulsed (60 T and, in one case, up to 74 T) magnetic fields at temperatures between 1.5 and 300 K. Tm 2Fe17 is a ferrimagnet with TC = 295 K and a spontaneous moment of 22 μB/f.u. at T = 4.2 K. Of particular interest are low-temperature magnetization curves along the sixfold crystal axis c, which is an easy direction in Tm2Fe17 and a hard direction in the deuteride. In either case the magnetization increases with magnetic field undulatorily in broad steps whose height is a multiple of the atomic moment of Tm, μTm = 7 μB. In Tm 2Fe17, the positions of the steps yield information on the Fe-Tm molecular field, 48 T on the Tm 2d site and 60 T on the Tm 2b site, whereas the crystal field parameter A66 is found from the widths of the steps: A66(b) = -35 Ka0-6 and A66(d) = -26 Ka0-6 (here a0 is the Bohr radius). It also proves possible to estimate the other sixth-order crystal field parameter: A60 ∼ -4 Ka0-6 (on average for both sites). Less information can be extracted from the powder data for the deuteride. Thus, the mean molecular field on Tm in Tm2Fe 17D3.2 is found to be 49 T or 9% less than in the parent binary compound. © 2013 American Physical Society