Magnetocrystalline Anisotropy of Ni-Pd Alloys

The magnetocrystalline anisotropy constants of disordered Ni-Pd alloys containing 20, 30, 40, 50, 60, 75 and 90 at% Pd have been studied in a range from 4.2 K up to the Curie temperature T c by the use of the torque method. At 0 K, the first anisotropy constant K 1 of 20% Pd is much the same as that of Ni. Then K 1 varies rapidly accompanying a change in sign from negative to positive at 50% Pd and takes the maximum at about 65% Pd. The higher order constants K 2 and K 3 show a complicated dependence on the content of Pd. As temperature is raised, K 1 of the alloys with negative K 1 at 0 K changes the sign likewise Ni and the reduced temperature T / T c where the sign changes, lowers as Pd increases. For the alloys with positive one, it decreases monotonically. Discussions are qualitatively made on K 1 .