MAGNETIC MOMENTS AND COERCIVE FORCE OF Tb 1-x Gd x Fe 2

The magnetization curves, the Curie temperature and the thermal dependence of the coercive force in the pseudobinary cubic Laves phase compounds Tb 1-x Gd x Fe 2 (0≤x≤l) has been measured. The saturation magnetization decreases almost linearly from TbFe 2 to GdFe 2 . The magnetic moment of the iron atoms is a constant(μ Fe -1.60±0.04μ B ) for the whole concentration range, while the moment of terbium atoms is smaller slightly than its free ion value of gJ = 9.0μ B due to crystal-field effects. The coercive field has got two contributions: one cames from the intrinsic pinning of domain walls in the Peierls crystal pontential wells and the fluctuation of magnetocrystalline anisotropy at rare-earth site; this contribution is preponderant at low temperatures, decaying exponentially with increasing temperature. The other comes from the pinning of domain walls by the internal stresses, causing the appearance of free magnetic poles.