First-principles determination of the rhombohedral magnetostriction of Fe100-xAlx and Fe100-xGax alloys

Through systematic density functional calculations using the full potential linearized augmented plane-wave (FLAPW) method, the rhombohedral magnetostriction (lambda(111)) of Fe100-xAlx and Fe100-xGax alloys are studied for x up to 25. Theoretical calculations satisfactorily reproduce the main features of experimental lambda(111)(x) curves, except for dilute alloys with x < 5. Detailed analyses on electronic and structural properties indicate the importance of availability and symmetry of dangling bonds for the sign change of lambda(111) around x = 16. In addition, the impurity induced local distortion might be a possible reason for the disagreement between theory and experiment for lambda(111) of the bulk bcc Fe. DOI: 10.1103/PhysRevB.86.224410