Acoustic-assisted magnetic-field-induced strain and stress output of Ni-Mn-Ga single crystal

摘要

The application of acoustic energy input from a piezoelectric actuator is observed to increase the magnetic-field-induced strain (MFIS) and decrease the threshold field in Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs). To appreciate better the benefit of the acoustic assistance, the stress and strain outputs of the quasistatic FSMA actuation under acoustic assistance are studied systematically. With acoustic assistance, the maximum reversible strain increases from 3% to 4.5% and appears in a broader range of stress output between 0.4 and 1.2 MPa. Elastic stress wave analysis explains quantitatively the effect of acoustic assistance on MFIS.