摘要
In the present work,the structure,magnetic properties,and cryogenic magnetocaloric effect of weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are reported through powder X-ray diffraction,bulk susceptibility,and heat capacity measurements,as well as scaling law analysis and a mean-field approach.A remarkably large isothermal magnetic entropy change of 354.0 m J K^(-1)cm^(-3)is observed for Gd_(3)SbO_(7)under an external field of 9 T at 2.0 K.The relative cooling power is estimated to be 618.9 J kg^(-1)(4.8 J cm^(-3))for an applied field of 8.9 T,with the largest adiabatic temperature change being 22.4 K at 6.3 K.The magnetocaloric performance of these oxides is quite impressive when compared with the benchmark magnetic refrigerant,gadolinium gallium garnet(Gd_(3)Ga_(5)O_(12),GGG).Therefore,Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are promising alternatives for cryogenic cooling techniques,especially for the magnetic liquefaction of helium.
基金
supported by the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant Nos.JCYJ20190808152217447,JCYJ20180305125212075,JCYJ20180507182246321,and JCYJ20210324095611032)
the National Natural Science Foundation of China(Grant Nos.51925804,11904236,11934017,and 11921004)
the Beijing Natural Science Foundation(Grant No.Z200007)
the National Key R&D Program of China(Grant Nos.2018YFE0103200,and 2018YFA0305700)
the Chinese Academy of Sciences(Grant No.XDB33000000)
the support from the Young Innovative Talents Project for Regular Universities in Guangdong Province(Grant No.2018KQNCX396)。
