Large spontaneous shape memory and magnetic-field-induced strain in Ni51Mn25.5Ga23.5 single crystals

Single crystals of Ni₅₁Mn_25.5Ga_23.5 were grown in [001] direction of parent phase by the Czochralski method. A two-way thermoelastic shape memory with a larger spontaneous strain of 1.62% in the Ni₅₁Mn_25.5Ga_23.5 crystal, noting without a prestress or an external magnetic field is reported. found. The results are discussed with reference to growth mechanism of single crystals and magnetic anisotropy produced by the preferential orientation of variants.

Single crystals of Ni₅₁Mn_25.5Ga_23.5 were grown in [001] direction of parent phase by the Czochralski method. Grown crystals were annealed at 1073 K for four days, and then quickly cooled to room temperature. The measured sample was a prism-shaped single crystal, cut in the {100} faces of the parental cubic L2₁ structure. Characteristic points for transition are determined by ac susceptibility and resistance measurements (figure 1, no listed).