Stable magnetic-field-induced strain above 1% in polycrystalline Ni-Mn-Ga

Polycrystalline Ni-Mn-Ga samples were directionally solidified and trained in order to lower the twinning stress. Polyurethane was used to fill the cracks. Magnetic-field-induced strain (MFIS) was measured in a rotating magnetic field over more than 106 cycles. The operating temperature was varied between 0 and 45 °C. With increasing temperature, the MFIS increased from 0.6% to 1.2%. After cooling to room temperature, an enhanced MFIS of 1.0% was retained and maintained over another 106 cycles.