MAGNETOHISTORY EFFECTS AND SPIN REORIENTATIONS OF ND3FE29-XTX AND ND3FE29-XTXN4 (T=V AND CR) COMPOUNDS

The novel compounds Nd3Fe29-xTx (T=V and Cr) have been successfully sy nthesized. Their x-ray patterns can be indexed with a monoclinic symme try and the A(2/m), space group. The Curie temperatures of Nd3Fe29-xTx are 455 and 413 K for T=V and Cr, the saturation magnetization at 4.2 K and room temperature are 54.7 and 46.8 mu(B)lf.u, for T=V and 49.9 and 32.2 mu(B)/f.u. for T=Cr, and the anisotropy fields at 4.2 K and r oom temperature are 12.8 and 2.4 T for T=V and 9.1 and 1.2 T for T=Cr, respectively. The spin reorientations of the easy magnetization direc tion of Nd3Fe29-xTx are observed at around 230 K for T=V and 135 K for T=Cr, respectively. After nitrogenation the relative volume expansion was about 6%, Curie temperature of each nitride increased about 50%, and the transition temperature T-sr of the spin reorientations of the nitride also increased 145 K for T=V and 250 K for T=Cr, respectively, compared with its parent compound. Nitrogenation resulted in remarkab le improvements in the saturation magnetization and anisotrspy fields at 4.2 K and room temperature. Magnetohistory effects for Nd3Fe29-xTx and Nd3Fe29-xTxN4 (T=V and Cr) in a low field have been observed. (C) 1997 American Institute of Physics.