Magnetism, phase transition, and magnetocaloric effects of Co2Nb0.8Ga1.2 and Co2Nb1.2Ga0.8 Heusler alloys

Abstract

Magnetism, phase transition, and magnetocaloric effects of Co2Nb0.8Ga1.2 and Co2Nb1.2Ga0.8 alloys were studied. The measured data show that the TC of Co2Nb1.2Ga0.8 and Co2Nb0.8Ga1.2 are 390 K and 250 K, respectively. Interestingly, calculated the high magnetic susceptibility and spontaneous magnetic moment special magnetic behavior was discovered. The spin fluctuation theory was used to prove the character of flowing electron ferromagnet characteristics in this series of alloys find the T0 and TA of the Co2Nb0.8Ga1.2 alloy are 0.268×103 K, and 0.984×103 K, respectively. Meanwhile, from the magnetocaloric effect, it can be found that the isothermal magnetic entropy change ΔSM was 1.8 J/kg⋅K of under a 5 T field while possessing a large refrigeration temperature region. The results show that changing the ratio of the Nb atom to the Ga atom can effectively reduce the Curie temperature and lay the foundation for the subsequent design of room temperature refrigerants.