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

Magnetostrictive behaviors of Fe_100-xB_x(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, λ_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 held of 1 kOe which is larger than the anisotropy held of the material. Variations of λ₁₀₀ and λ₁₁₁ values are estimated as a function of B content. λ₁₀₀ of Fe-B hlm shows a positive value and increases with increasing the B content from 0 to 13 at. %, while the value of λ₁₁₁ changes from negative to positive with increasing the B concentration. The B content dependence of λ_s for poly-crystalline Fe-B samples is explained by considering the B content dependence of λ₁₀₀ and λ₁₁₁ determined with single-crystal film samples.