First principles determination of magnetostriction in bulk transition metals and thin films

The magnetostriction coefficients (λ₀₀₁) of bulk magnetic transition metals (BCC Fe, FCC Co and Ni) and overlayers (Co/Cu(0 0 1) and Co/Pd(0 0 1)) are directly calculated from first principles using the local density full potential linearized augmented plane wave method. The essential ingredient that permits this determination is our finding that the magneto-crystalline anisotropy is a linear function of the lattice strain when computed with the new precise state tracking and torque approaches. The calculated bulk λ₀₀₁ values agree well with experiment, which appears to validate the present approach for determining the tiny magnetostriction in transition metal systems. Interestingly, the calculated λ₀₀₁ at the Co/Cu(0 0 1) and Co/Pd(0 0 1) interfaces differ in sign and magnitude (-5.7 × 10^-5 and +2.3 × 10^-4, respectively) with the different hybridization between the Co-d_xz,yz and the underlying substrate d states playing the key role.