Giant low field magnetocaloric effect near room temperature in isostructurally alloyed MnNiGe-FeCoGe systems

According to the strategy of isostructural alloying, the magnetostructural coupling was realized by doping appropriate stable hexagonal Ni2In-type FeCoGe alloy into MnNiGe systems, which results in the achievement of large magnetization difference and giant low field magnetic entropy change (.Sm) in the isostructurally alloyed (MnNiGe)-(FeCoGe) systems. Giant.Sm as much as -51.3 J.kg(-1)K(-1) at 296 K and -56.2 J.kg(-1)K(-1) at 275 K under 5 T magnetic field have been observed in (MnNiGe)(0.91)-(FeCoGe)(0.09) and (MnNiGe)(0.89)-(FeCoGe)(0.11) alloys, respectively. Moreover, the.Sm of (MnNiGe)(0.89)-(FeCoGe)(0.11) alloy are reached -25.6 J.kg(-1)K(-1) (2 T) and -43.6 J.kg(-1)K(-1)(3 T), respectively. The observed values of -.SM under the magnetic field of 2 T and 3 T are larger than most of the reported MnMX(M = Co, Ni and X = Ge, Si) based systems.