Magnetic anisotropy of new intermetallic compound SmFe7

We characterized the magnetocrystalline anisotropy of a novel intermetallic compound, SmFe7, by means of torque measurement. Single crystal of SmFe7 was grown by the self-flux method using Sm as a flux. From an analysis of the torque curves in the (001) and (100) planes using the least mean squares method, we found that the tetragonal anisotropy constants K-1, K-2 and K-3 of SmFe7 an -8.7+/-0.4 (x 10(7) erg/cm(3)), 1.4+/-0.3 (x 10(7) erg/cm(3)), and -2.7+/- 0.1 (x 10(6) erg/cm(3)) at 293 K, respectively. The reliability of these values was confirmed using the results of magnetization measurements. The huge magnetocrystalline anisotropy of SmFe7 is superior to that of Nd2Fe14B. SmFe7 appears to he a promising host material for a high-performance hard magnet.