Frequency response of single crystal Ni-Mn-Ga FSMAs

摘要

Magnetic-field-induced strain in single crystals of Ni-Mn-Ga magnetic shape memory alloys were studied under cyclic field conditions using a compression spring to reset the sample as H → 0. Low frequency actuation strain of 2.5% degraded to about 1.5% at an actuation frequency of 500 Hz. Two resonant-like features appear in the ε (f) data, which appear to correspond to a broad test system resonance (100 - 200 Hz) and a sample longitudinal resonance near 350 Hz. The relative phase of field and strain support the assignment of the 350 Hz resonance to the sample.