Thermal strain and magnetization of the ferromagnetic shape memory alloy Ni52Mn25Ga23 in a magnetic field

Magneto-Structural Properties of Ni2MnGa Ferromagnetic Shape Memory Alloy in Magnetic Fields

“…Recently, Sakon et al [19] investigated the correlation between magnetism and crystallographic structures as it relates to the martensite transformation of Ni 52 Mn 25 Ga 23 , which undergoes the martensite transformation below T C [6,7]. The current study particularly focused on the physical properties in magnetic fields.…”

“…One is martensitic transformation, shown in Figure 5, and the other is magnetostriction [19]. In the former case, the driving force is originated from phase transformation.…”

“…Here, we analyzed that by using the polycrystal samples, it is possible to provide information on the easy axis of the magnetization in the martensite structure with temperature-dependent strain measurements under the constant magnetic fields. Thermal strain, permeability, and magnetization measurements were performed for polycrystal Ni 52 Mn 25 Ga 23 in magnetic fields (B), and magnetic phase diagrams (B-T phase diagram) were constructed [19]. Thermal strain measurements (linear thermal expansion) and magnetostriction measurements were performed using strain gauges (Kyowa Dengyo Co. Ltd., Chofu, Japan) under steady fields.…”

“…Sakon et al [19] measured the strain for polycrystal Ni 52 Mn 25 Ga 23 . At zero magnetic field, the strain is 3.6 × 10 −4 ( Figure 5).…”

“…On the contrary, the thermal strain under the magnetic field of 5 T at 300 K in the ferromagnetic martensite phase was 720 ppm, indicating that the field aligned some of the twin variants. The magnetostriction at 300 K in the ferromagnetic martensite phase at 10 T is −100 ppm [19].…”