Large field induced strain in single crystalline Ni–Mn–Ga ferromagnetic shape memory alloy

摘要: A room temperature free shear strain of 5.7% is reported in a single crystal Ni–Mn–Ga having composition close to the Heusler alloy Ni2MnGa. twin boundary was created 2 mm×2 mm×25 mm using permanent magnet with surface field strength about 320 000 A/m. sharp 6.5° bend occurs sample at boundary. The magnetization changes abruptly across this By moving relative edge magnet, we were able sweep back and forth along length. Surface measured Hall probe results confirm that easy axis tetragonal c axis. Powder x-ray diffraction shows fcc body-centered-tetragonal bct martensitic transition material involved 6% reduction cell c/a ratio, from √ 1.33. maximum achievable thus estimated be 6.2%. planes system are {112}bct observed lie almost normal long tested.