Magnetocrystalline anisotropy and Fermi surface of Ni3Al

Abstract
The first magnetocrystalline anisotropy constant K1(T,H) has been measured in stoichiometric single crystals of weakly ferromagnetic Ni3Al as a function of magnetic field in the range 1≲H≲48 kG at T=4.2 K and of temperature in the range 1.2≲T≲43 K at H=16 kG. At 4.2 K and 16 kG we obtain K1=−(9.6±0.7)103 erg cm3, a value reproduced within experimental error in three samples investigated having residual resistivity ratios [ρ(293 K)/ρ(4.2 K)] 17, 18, and 34, respectively. The measured value of K1 has the same sign but is about one hundred times smaller in magnitude than in pure Ni at the same temperature and field. Within our experimental field and temperature ranges we observe a relatively weak field dependence above 5 kG but a rapid temperature variation of K1(T,H) which falls with increasing temperature in proportion to a high power of the relative magnetization M(T,H)/M(0,H). Qualitative interpretations of these results are suggested.