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Fe50Mn15-xCoxNi35(x=0,1,3,5,7)alloys were prepared by arc melting under purified argon atmosphere.The ingots were homogenized at 930°C for 90h followed by water quenching.The crystal structure,magnetic properties and magnetocaloric effects of the alloys were studied by X-ray diffraction(XRD)and MPMS-7-type SQUID.The results show that all samples still maintained a single-(Fe,Ni)-type phase structure.With the increase of the content of Co,the Curie temperatures of these alloys increased and exhibited a second-order magnetic transition from ferromagnetic(FM)to paramagnetic(PM)state near Curie temperature.The maximum magnetic entropy change and the relative cooling power of Fe50Mn10Co5Ni35alloy was 2.55 J/kg·K and 181 J/kg,respectively,for an external field change of 5T.Compared with rare earth metal Gd,Fe50Mn15-xCoxNi35 series of alloys have obvious advantage in resource price;their Curie temperatures can be tuned to near room temperature,maintain a relatively large magnetic entropy change at the same time and they are a type of potential magnetic refrigeration materials near room temperature.
Fe50Mn15-xCoxNi35 (x = 0,1,3,5,7) alloys were prepared by arc melting under purified argon atmosphere. The ingots were homogenized at 930 ° C for 90h followed by water quenching.The crystal structure, magnetic properties and magnetocaloric effects of the alloys were studied by X-ray diffraction (XRD) and MPMS-7-type SQUID. The results show that all samples still maintained a single- (Fe, Ni) -type phase structure .With the increase of the content of Co, the Curie temperatures of these alloys increased and exhibited a second-order magnetic transition from ferromagnetic (FM) to paramagnetic (PM) state near Curie temperature. The maximum magnetic entropy change and the relative cooling power of Fe50Mn10Co5Ni35alloy was 2.55 J / kg · K and 181 J / kg, respectively, for an external field change of 5T.Compared with rare earth metal Gd, Fe50Mn15-xCoxNi35 series of alloys have obvious advantages in resource price; their Curie temperatures can be tuned to near room temperature, maintain a relatively large magnetic entropy ch ange at the same time and they are a type of potential magnetic refrigeration materials near room temperature.