Magnetic Anisotropy in Co and Co-Ni Single Crystals Deformed by Cold Rolling

A study of the magnetic anisotropy induced by cold rolling was made for h.c.p. Co and Co-Ni single crystals containing 10 and 20 at %Ni by using a torque magnetometer. The observed induced uniaxial anisotropy K ur for Co was found to be maximum, -5×10 5 erg/cm 3 , at about R =5%, where the direction of the easy axis was parallel to the rolling direction. For the 10%Ni-Co alloy, the similar dependence of K ur on R was observed, although the sign in K ur was changed from negative to positive for R around 30%. For the 20%Ni-Co alloy, the values of K ur was found to increase with R and to be about 4×10 5 erg/cm 3 at R =60%. The results are discussed in terms of the magnetoelastic coupling energy associated with lattice defects and also in connection with the slip induced directional order.