Structural and magnetic properties of R/sub 2/Fe/sub 14/B compounds
A new class of Fe rich ternary compounds of the formula R/sub 2/Fe/sub 14/B has been discovered independently in this and other laboratories. Structural and magnetic properties of R/sub 2/Fe/sub 14/B (R = Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Lu) are reported as well as the related pseudoternaries (Nd/sub 1-x/R/sub x/)/sub 2/Fe/sub 14/B (R = Y, Ce, Gd, Tb, Dy, Ho, Er) and Nd/sub 2/(Fe/sub 1-x/T/sub x/)/sub 14/B (T = Cr, Mn, CO, Ni, Al). Results of magnetization measurements on aligned powder samples of R-Fe-B system are presented over the temperature range 4.2 to 1000 K. The magnetic ordering temperatures, T/sub c/, are dominated by the Fe, Fe interaction while the magnetic anisotropy at low temperatures arises from the crystal fields of the R ions. The R/sub 2/Fe/sub 14/B compounds have either axial anisotropy (R = Y, Ce, Pre, Nd, Gd, Tb, Dy, Ho, Lu) or planar anisotropy (R = Sm, Er, Tm). The overall Fe sublattice shows axial anisotropy over the temperature range investigated (4.2 K near T/sub c/). For Nd/sub 2/Fe/sub 14/B and Ho/sub 2/Fe/sub 14/B, a spin reorientation is observed near 140 and 62 K, respectively. This spin reorientation is explained in terms of a competition between the second and fourth order crystal field parameters, respectively. For Er/sub 2/Fe/sub 14/B, a second type of spin reorientation occurs around 326 K, which is interpreted in terms of competing anisotropy of the R and Fe sublattice, the latter having only a small temperature dependence.
- Research Organization:
- California Univ., San Diego (USA)
- OSTI ID:
- 6973235
- Country of Publication:
- United States
- Language:
- English
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