12% magnetic field-induced strain in Ni-Mn-Ga-based non-modulated martensite

Abstract

Magnetic field-induced strain (MFIS) of 12% is reported in ferromagnetic Ni46Mn24Ga22Co4Cu4 martensite exhibiting non-modulated (NM) tetragonal crystal structure with lattice parameter ratio c/a>1. The strain was measured at ambient temperature in a magnetic field of the order of 1 T. The twinning stress σTW and the magnetic stress σMAG were also measured and the condition for a giant MFIS observation σTW<σMAG was confirmed. The MFIS was achieved in NM Ni46Mn24Ga22Co4Cu4 martensite by considerable lowering of the σTW value as compared to the values for NM martensites in ternary Ni-Mn-Ga system.

Ab initiostudy of Ni2MnGa under shear deformation

“…However, a MFIS of 12% has recently been reported in the special case of NM phase with reduced (c/a) NM = 1.147, achieved by simultaneous doping by 4 at. % of Cu and Co [12]. In addition, a premartensite exists above the martensitic transformation temperature and exhibits cubic structure with symmetry reduced by modulation with periodicity of six lattice planes (6M) [13].…”

Non-Modulated Martensite Microstructure With Internal Nanotwins In Ni-Mn-Ga Alloys

“…To date, this is the main reason why the microstructure and other related properties of NM martensite has been less frequently studied [9][10][11]. However, very recently giant MFIS of 12% of longitudinal strain was observed by Sozinov et al [12] in NM Ni-Mn-Ga based single crystals opening new possibilities for NiMn-Ga system as a functional material. In particular, considering significantly higher temperature of martensitic transformation observed in NM structures expanding the narrow temperature range found in 10M and 14M martensites well above room temperature, which is very important for potential applications.…”

Thermodynamics and Kinetics of Martensitic Transformation in Ni-Mn-based Magnetic Shape Memory Alloys

“…Other FMSMAs, such as Fe-Pd [3], Fe-Pt [4], Ni-Mn-Al [5], Ni-Co-Ga [6], Ni-Co-Al [7] and NiFe-Ga [8], have successively been reported. In Ni-Mn-Ga systems, a huge MFIS of about 9.4 % has been reported in 14M [9] and about 12 % in non-modulated [10] martensites, despite the fact that the output stress is limited to several MPa [11,12].…”