Tuning Martensitic Phase Transition by Non-Magnetic Atom Vacancy in MnCoGe Alloys and Related Giant Magnetocaloric Effect
Li-Fu Bao1**, Wen-Deng Huang1,2, Ya-Jie Ren1
1School of Physics and Telecommunication Engineering, Shaanxi University of Technology, Hanzhong 723000 2MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, Department of Applied Physics, School of Science, Xi'an Jiaotong University, Xi'an 710049
Abstract：The effects of non-magnetic atom vacancy on structural, martensitic phase transitions and the corresponding magnetocaloric effect in MnCoGe$_{1-x}$ alloys are investigated using x-ray diffraction and magnetic measurements. The introduction of non-magnetic atom vacancy leads to the decrease of the martensitic transition temperature and realizes a temperature window where magnetic and martensitic phase transitions can be tuned together. Moreover, the giant magnetocaloric effect accompanied with the coupled magnetic-structural transition is obtained. It is observed that the peak values of magnetic entropy change of MnCoGe$_{0.97}$ are about $-$13.9, $-$35.1 and $-$47.4 J$\cdot$kg$^{-1}$K$^{-1}$ for $\Delta H=2$, 5, 7 T, respectively.
2016, Vol. 33 
