The origin of large magnetostrictive properties of rare earth doped Fe-Ga as-cast alloys

Abstract

Rare earth doping could greatly enhance the magnetostrictive properties of Fe-Ga as-cast alloys. But the origin of this large magnetostrictive property has always been controversial. Some researchers think that this large magnetostrictive property is induced by the distortion of A2 lattice. While others think this is sourced from the formation of (001) oriented textures. In order to solve this controversy, the microstructure and magnetic properties of La, Pr, Sm and Y doped Fe-Ga as-cast alloys were examined by scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), electron backscattered diffraction (EBSD), vibrating sample magnetometer (VSM) and strain gauge method in this paper. And the results show that the reason for the increase of the magnetostrictive properties of Fe-Ga cast alloys caused by rare earth doping is closely related to whether the rare earth elements enter the A2 crystal lattice. When the rare earth elements cannot enter into the A2 lattice of the alloy sample, the cause of the large magnetostriction is mainly attributed to the (001)-oriented columnar crystals. However, when rare earth elements can enter into the A2 crystal lattice of the alloy sample, the cause of large magnetostriction is mainly due to residual stress, or distortion caused by rare earth elements entering into the A2 crystal lattice, and secondly by the (001)-oriented columnar crystals.