Elasticity and magnetism of Ni2 MnGa premartensitic tweed. Issue 10 (22nd April 2014) - Seiner, Hanuš
Abstract Magnetic, magneto‐elastic and elastic measurements were used to characterize the thermal evolution of the premartensite phase of Ni2 MnGa. The premartensitic transition is shown to correspond to a sharp maximum of magnetostriction and a pronounced minimum of the (110) 〈11‾0〉 shear stiffness (the c′ elastic coefficient); no additional softening of the c′ coefficient prior to the martensitic transformation was observed. In contrast, a significant softening of the (100) 〈010〉 stiffness (the c44 elastic coefficient) was observed in the vicinity of the martensitic transition, while this coefficient is fully unaffected by the premartensitic transition. A simple two‐dimensional model of the tweed is presented to explain this mutual independence between the c′ and c44 shears and the effect of tweed formation on both of them.