Effect of Hydrostatic Pressure on P-14M-2M and P-2M Martensitic Transformations in Single Crystalline Ni–Mn–Ga Ferromagnetic Shape Memory Alloys

Effect of hydrostatic pressure on martensitic transformation in a ferromagnetic shape memory alloy Ni2MnGa

“…Then we obtain V/V I = −1.0 × 10 −3 , meaning that Ni 2 MnGa contracts by 0.10% in volume in association with the I → M transformation. This volume change is the same order as that of the P → 2M and the P → 14M transformations in Ni-Mn-Ga alloys [29], which implies the validity of the present experimental result of hydrostatic pressure dependence of martensitic transformation temperature. Incidentally, in order to evaluate such a small volume change from the change in lattice parameters, the value of lattice parameters should be given in the precision of five digits for both the I-and M-phases, but there is no available experimental result of lattice parameters evaluated in such a high precision.…”

Investigations on the electronic transport and piezoresistivity properties of Ni2−XMn1+XGa (X = 0 and 0.15) Heusler alloys under hydrostatic pressure

“…17,33 Similar q (T) has been observed for X ¼ 0.15 (Figure 1(b)), where the application of pressure increases the q due to the pressure induced phase transformation, which indicates the phase changes from pre-martensite to martensite. 25,26 However, overall q for X ¼ 0.15 is lower than X ¼ 0. Moreover, in contrast to X ¼ 0, substantial thermal hysteresis is observed for all the pressure.…”

“…23 Clear view of magneto structural transition has been investigated in Ni 2.18 Mn 0.82 Ga. 24 Temperature dependence of electrical resistivity under various hydrostatic pressures has been studied for Ni 2.14 Mn 0.84 Ga 1.02 , Ni 2.14 Mn 0.92 Ga 0.94 , and Ni 2 MnGa single crystals. 25,26 Large value of piezoresistance and magnetoresistance under uniaxial stress has been observed in Ni 45 Co 5 Mn 37.5 In 12.5 . 27 In this work, we investigate the effect of hydrostatic pressure on the resistivity and piezoresistivity (PR) of Ni 2ÀX Mn 1þX Ga (X ¼ 0 and 0.15) magnetic shape memory alloys.…”

Effect of Hydrostatic Pressure on P–14M–2M Martensitic Transformation in Ni2.14Mn0.84Ga1.02

“…The increasing ratios against hydrostatic pressure are about 4.2 and 15.9 K/GPa, respectively and they are almost identical to the values obtained in the previous work where the applied pressure was only 1GPa. 3) As we expected before, when the hydrostatic pressure is higher than 8GPa, the 2M martensite phase directly forms in the parent phase at 310K. We have evaluated the atomic volume changes associated with the P-14M and 14M-2M martensitic transformations by the Clausius-Clapeyron equation and the values obtained are -0.05 and -0.04 %, respectively.…”