Effect of martensitic structure on the magnetic field controlled damping effect in a Ni–Fe–Mn–Ga ferromagnetic shape memory alloy

• DOI: 10.1007/s10853-017-1399-5
• Publication Date: 2017-07-31T15:04:37Z
• Authors: Yu Wang; Chonghui Huang; Haijun Wu; Xiaoqi Liao; Jinghui Gao; Dong Wang; Sen Yang; Xiaoping Song
• Keywords: Magnetic shape-memory alloy; Magnetocrystalline anisotropy; Tetragonal crystal system; Damping capacity; Magnetic damping

We investigated the effect of martensitic structure on the magnetic field controlled damping effect in a Ni53Fe2Mn20Ga25 polycrystalline ferromagnetic shape memory alloy, which undergoes the structure transitions in the sequence of parent phase → seven-layer modulated (14M) martensite → non-modulated tetragonal martensite. We found that large increase in damping capacity by applying magnetic field appears in the 14M martensite, but insignificant increase is observed in the non-modulated tetragonal martensite. This demonstrates that the magnetic field controlled damping effect is strongly dependent on the martensitic structure. It is proposed that magnetic field controlled damping effect relies on the twinning stress and magnetic stress of martensite. Large magnetic field controlled damping effect is expected to appear in the martensitic structure with large magnetocrystalline anisotropy and small twin shear.