title: Two successive magneto-structural transformations and their relation to enhanced magnetocaloric effect for Ni55.8Mn18.1Ga26.1 Heusler alloy.
abstract: In the present work, two successive magneto-structural transformations (MSTs) consisting of martensitic and intermartensitic transitions have been observed in polycrystalline Ni55.8Mn18.1Ga26.1 Heusler alloy. Benefiting from the additional latent heat contributed from intermediate phase, this alloy exhibits a large transition entropy change ΔStr with the value of ~27 J/kg K. Moreover, the magnetocaloric effect (MCE) has been also evaluated in terms of Maxwell relation. For a magnetic field change of 30 kOe, it was found that the calculated value of refrigeration capacity in Ni55.8Mn18.1Ga26.1 attains to ~72 J/kg around room temperature, which significantly surpasses those obtained for many Ni-Mn based Heusler alloys in the same condition. Such an enhanced MCE can be ascribed to the fact that the isothermal entropy change ΔST is spread over a relatively wide temperature interval owing to existence of two successive MSTs for studied sample.
authors.affiliation: College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Xu
authors.affiliation: College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China.
authors.forename: Yuanlei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China.
authors.forename: Chang
authors.initials: C
authors.lastname: Tao
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Zheng
authors.affiliation: Department of Physics, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Jing