The magnetic properties and magnetocaloric effects of amorphous and crystalline Gd55Co35Ni10 ribbons are investigated.A main phase with a Ho 12 Co 7-type monoclinic structure(space group P21/c) and a minor phase with ...The magnetic properties and magnetocaloric effects of amorphous and crystalline Gd55Co35Ni10 ribbons are investigated.A main phase with a Ho 12 Co 7-type monoclinic structure(space group P21/c) and a minor phase with a Ho4Co3-type hexagonal structure(space group P63/m) are obtained for crystalline ribbon after annealing.The amorphous ribbons order ferromagnetically and undergo a second-order transition at 192 K.For crystalline Gd55Co35Ni10 ribbons,two magnetic phase transitions occur at 158 and 214 K,respectively.The peak value of-△SM under a field change of 0-5 T is 6.5 J/kg K at 192 K for amorphous Gd55Co35Ni10 ribbons.A relatively large magnetic entropy change(～5.0 J/kg K) under a field change of 0-5 T for the crystalline Gd55Co35Ni10 ribbons is obtained in the temperature interval range of 154-214 K.The large platform of magnetic entropy change and the negligible thermal/magnetic hysteresis loss mean the crystalline Gd55Co35Ni10 compound can satisfy the requirement of the Ericsson-type refrigerator working in the temperature range from 154K to 214K.展开更多
(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds for magnetic refrigeration were studied by X-ray diffraction, ac susceptibility and isothermal magnetization measurements. X-ray powder diffraction shows that all the c...(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds for magnetic refrigeration were studied by X-ray diffraction, ac susceptibility and isothermal magnetization measurements. X-ray powder diffraction shows that all the compounds have hexagonal Ce2Ni7-type structure. The Curie temperatures(TC) are 258 K and 222 K for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. High coercivities(HC) of about 1.74 and 6.61 k Oe at 5 K with a smooth demagnetization curves were obtained for the(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. For an applied field change from 0 to 50 k Oe, the maximum(??SM) for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds are 0.52 and 0.67 J/(kg K), respectively.展开更多
基金supported by the Guangdong Provincial Science and Technology Program(Grant Nos.2010B050300008,2009B090300273 and 2007B010600043)the Guangzhou Municipal Science and Technology Program(Grant No.12F582080022)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (Grant No.x2clB7120290)the Fundamental Research Funds for the Central Universities(Grant Nos.2011ZM0014 and 2012ZZ0013)
文摘The magnetic properties and magnetocaloric effects of amorphous and crystalline Gd55Co35Ni10 ribbons are investigated.A main phase with a Ho 12 Co 7-type monoclinic structure(space group P21/c) and a minor phase with a Ho4Co3-type hexagonal structure(space group P63/m) are obtained for crystalline ribbon after annealing.The amorphous ribbons order ferromagnetically and undergo a second-order transition at 192 K.For crystalline Gd55Co35Ni10 ribbons,two magnetic phase transitions occur at 158 and 214 K,respectively.The peak value of-△SM under a field change of 0-5 T is 6.5 J/kg K at 192 K for amorphous Gd55Co35Ni10 ribbons.A relatively large magnetic entropy change(～5.0 J/kg K) under a field change of 0-5 T for the crystalline Gd55Co35Ni10 ribbons is obtained in the temperature interval range of 154-214 K.The large platform of magnetic entropy change and the negligible thermal/magnetic hysteresis loss mean the crystalline Gd55Co35Ni10 compound can satisfy the requirement of the Ericsson-type refrigerator working in the temperature range from 154K to 214K.
基金supported by the U.S.Department of Energy,Office of Basic Energy Science,Division of Materials Sciences and EngineeringThe research was performed at the Ames Laboratory.Ames Laboratory is operated for the U.S.Department of Energy by Iowa State University under contract No.DE-AC02-07CH11358+2 种基金ZHONG X C also thanks the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Education Ministry of China(Grant No.x2cl B7120290)the Guangzhou Municipal Science and Technology Program(Grant No.12F582080022)the Fundamental Research Funds for the Central Universities of China(Grant Nos.2012ZZ0013 and 2014ZZ0005)
文摘(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds for magnetic refrigeration were studied by X-ray diffraction, ac susceptibility and isothermal magnetization measurements. X-ray powder diffraction shows that all the compounds have hexagonal Ce2Ni7-type structure. The Curie temperatures(TC) are 258 K and 222 K for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. High coercivities(HC) of about 1.74 and 6.61 k Oe at 5 K with a smooth demagnetization curves were obtained for the(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds, respectively. For an applied field change from 0 to 50 k Oe, the maximum(??SM) for(La0.5Ce0.5)2Co7 and(Ce0.65Pr0.35)2Co7 compounds are 0.52 and 0.67 J/(kg K), respectively.
