摘要
Upon substitution of Sn for Zn, the Curie temperature of Mn3ZnC is lowered from 380 to 375 K for MnzZno.gsSno.osC and to 305 K for Mn3Zno.75Sno.25C. In accordance with the second-order ferromagnetic-paramagnetic transition, a room-temperature magnetocaloric effect without thermal and magnetic hysteresis is observed over a wide temperature range. The maximum value of the magnetic-entropy change ABM for a magnetic-field change from 0 to 5 T is 2.42 J.kg^-1·-K^-1 at 386 K for Mn3Zno.95Sno.osC and 1.70 J·kg^-1.K^-1 at 308 K for Mn3Zn0.75Sno.25C. Meanwhile, substitution of Cr for Mn lowers the temperature of ferromagnetic-ferrimagnetic transition from 233 K for Mn3ZnC to 230 K for Mn2.9Cro.tZnC and to 175 K for Mn2.iCro.oZnC. An inverse magnetocaloric effect with △Bu equal to 0.28 J·kg^-1.K^-1 at 223 K for a field change from 0 to 1.47 T is observed for Mn2.gCro.zZnC.
Upon substitution of Sn for Zn, the Curie temperature of Mn3ZnC is lowered from 380 to 375 K for MnzZno.gsSno.osC and to 305 K for Mn3Zno.75Sno.25C. In accordance with the second-order ferromagnetic-paramagnetic transition, a room-temperature magnetocaloric effect without thermal and magnetic hysteresis is observed over a wide temperature range. The maximum value of the magnetic-entropy change ABM for a magnetic-field change from 0 to 5 T is 2.42 J.kg^-1·-K^-1 at 386 K for Mn3Zno.95Sno.osC and 1.70 J·kg^-1.K^-1 at 308 K for Mn3Zn0.75Sno.25C. Meanwhile, substitution of Cr for Mn lowers the temperature of ferromagnetic-ferrimagnetic transition from 233 K for Mn3ZnC to 230 K for Mn2.9Cro.tZnC and to 175 K for Mn2.iCro.oZnC. An inverse magnetocaloric effect with △Bu equal to 0.28 J·kg^-1.K^-1 at 223 K for a field change from 0 to 1.47 T is observed for Mn2.gCro.zZnC.
基金
supported by the Dr Research Start-up Fund of Shenyang Ligong University (No. 2008 (20))
the National Natural Science Foundation of China (No.50902128)
the Natural Science Foundation of Jilin Province, China (No. 20101534)
