Temperature stability of magnetic field-induced strain and field-controlled shape memory effect on Ni/sub 52/Mn/sub 16.4/Fe/sub 8/Ga/sub 23.6/ single crystals

The temperature dependence of the magnetic field-induced strain (MFIS) and the field-controlled shape memory effect in Ni/sub 52/Mn/sub 16.4/Fe/sub 8/Ga/sub 23.6/ single crystals were investigated by measuring the MFIS and measuring the magnetic field-enhanced transformation strain with a field bias applied in the [001] and [010] directions of the parent phase, respectively. The results show that such material combined with the martensitic transformation can product large field-enhanced transformation strain and large MFIS. The strain accompanying the martensitic transformation is -1.61% in zero field and can be enhanced to -3.30% by a field of 960 kA/m. A MFIS of 1.04% has been induced along [001] in unstressed crystals with saturated magnetic field of 600 kA/m applied along the same direction at near martensitic transformation temperature. It was found that the MFIS is almost temperature independent; the maximum decrease of the saturated MFIS is less than 10%, from 265 K to 100 K. This well-behaved temperature response makes this alloy particularly valuable for industrial and military smart actuators and transducers. Furthermore, it was found that the direction in which the MFIS has the largest value is always the [001], namely, the growth direction of the crystals.