Magnetostrictive Behavior of Fe-B(001) Single-Crystal Films Under Rotating Magnetic Fields

Magnetostrictive behaviors of Fe100-xBx(001), x = 0, 5, and 13 at. %, single-crystal films are studied in comparison with those of poly-crystal Fe-B films under rotating magnetic fields. The output waveform of poly-crystal Fe-B film is sinusoidal and the saturation magnetostriction, lambda(s), varies from negative to positive with increasing the B composition, x, from 0 to 13 at. %. On the other hand, the output waveform of single-crystal Fe-B film is bathtub-like when measured along the easy magnetization axis of bcc[100], while it changes to triangular when measured along the hard magnetization axis of bcc[110]. The output waveform is strongly influenced by the magnetocrystalline anisotropy under a magnetic field of 1 kOe which is larger than the anisotropy field of the material. Variations of lambda(100) and lambda(111) values are estimated as a function of B content. lambda(100) of Fe-B film shows a positive value and increases with increasing the B content from 0 to 13 at. %, while the value of lambda(111) changes from negative to positive with increasing the B concentration. The B content dependence of lambda(s) for poly-crystalline Fe-B samples is explained by considering the B content dependence of lambda(100) and lambda(111) determined with single-crystal film samples.