Magnetocrystalline Anisotropy of Nickel-Cobalt Alloys

Abstract

An experimental study of the magnetocrystalline anisotropy for Ni–Co alloys has been carried out from 0% to 64% Co concentration and also between 77 and 700 K. The concentration dependence of the magnetocrystalline anisotropy constant K₁ can be described in the form K₁(x)=a+bx+Aexp(−αx), a, b, α and A: constant; x: concentration of cobalt). The temperature where K₁=0 was determined as a function of x and it was found that the diagram of K₁ in the Ni–Co alloy system could be classified into three concentration ranges. The temperature dependence of K₁ has been discussed, based on the result by Carr: K₁(T)=K₁(0)(1−βT⁄T_c)(M_s(T)⁄M_s(0))ⁿ. The value of n and β were estimated as a function of x, and both n and β show an abrupt change around 8%Co where K₁ changes from negative to positive.