Decoupling the anisotropic magnetization processes for the bulk Galfenol via utilizing the entire 2D SANS patterns

Quantitative understanding of the magnetization processes (MPs) is one of the important aspects for the design and development of ferromagnetic smart materials (FSMs). The present work explores the method of decoupling the anisotropic MPs directly for bulk soft FSMs. The small-angle neutron scattering (SANS) measurements were performed on the [1 0 0]-oriented alloys Fe_1-xGa_x (Galfenol) under a series of magnetic fields. Those two-dimensional (2D) SANS patterns were decomposed and reconstructed by the spherical harmonic approaches. The scattering intensities, which are respectively decomposed into isotropic and anisotropic components, show clearly the pathway of three types of magnetic domains. The 90° domain process is thus quantified directly in the bulk Galfenol. The evolution trend for the domain process is consistent with that for the lattice strain and magnetization responses, which has been respectively evidenced by the in-situ neutron diffraction and initial magnetization measurement. Meanwhile, the quantitatively addressed domain process agrees well with the simulated results by the energy-based domain rotation modelling. These observations indicate that the anisotropic magnetization processes correlate tightly with the lattice strain response, which are of significant importance for the understanding and design of large magnetic-field-induced strain (MFIS). The present approach provides a quantitative method for decoupling the magnetization processes, which would be also applicable to other ferromagnetic systems besides Galfenol. This may help the understanding of MFIS mechanism and development of new FSMs.