1999 Volume 23 Issue 1_2 Pages 403-405
The magnetostatic critical point phenomena of a single crystalline Ni (fcc) were first investigated using a computer controlled vibrating sample magnetometer in the uniformly applied bipolar fields from 0 to ±8 kOe. The magnetization M was measured along both of the easy axis [111] and hard axis [100]. A clear kink point locus was observed for the whole critical region in the extremely low fields measurement and the spontaneous magnetization and the critical point were directly obtained without data reduction for both easy and hard axes. The critical indices for the easy axis and hard axis were obtained to be β=0.385 ±0.002 and 0.426±0.003, γ =1.302±0.003 and 1.19±0.01, and δ=4.27±0.01 and 3.80±0.01, respectively. The effect of the magnetocrystalline anisotropy on the critical indices is first found to be significantly large and not negligible in Ni. It was clearly shown that the Griffith's inequality is valid and the scaling low for the critical indices fails, and that all of the measured data for easy axis support the existence of the equation of statesΨ(H, M) but does not for the low field data at hard axis.
