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We report a systematic study of the specific heat and dc magnetic susceptibility on the paramagnetic to ferrimagnetic transition (TC~141 K) in CuNMn3. A large magnetocaloric effect (MCE) at TC is observed with the entropy change of 3.49 J/kg K (6.38 J/kg K) for the field change of ΔH=20 kOe (45 kOe). The analysis of the isothermal magnetizations, including the derived Arrott plots and magnetic entropy change, shows a second-order like transition at TC. However, the existence of latent heat around TC is unambiguously manifested by the reduced slope of the temperature-time relaxations recorded during the specific heat measurement, indicating the transition is in fact weakly first-order in nature. The large MCE comparable with those observed the antiperovskite manganese carbides suggests it is equivalently interesting to explore the MCE in the antiperovskite manganese nitrides as in the carbides. [ABSTRACT FROM AUTHOR]

Zero-field cooling (ZFC) exchange bias (EB) was observed in antiperovskite compounds Ga1- xNMn3+ x ( x = 0.06 and 0.1). The existence of ferromagnetic (FM) clusters has been demonstrated in a spin glass (SG) matrix. The ZFC-EB is suggested to originate from the unidirectional anisotropy formed isothermally along the FM/SG interface. For this typical physical system, both ways including the initial magnetization process and FC process could result in the unidirectional anisotropy. In addition, the training effect after ZFC is similar to those observed in conventional FC-EB systems. [ABSTRACT FROM AUTHOR]

Zero-field cooling (ZFC) exchange bias (EB) was observed in antiperovskite compounds Ga1- xNMn3+ x ( x = 0.06 and 0.1). The existence of ferromagnetic (FM) clusters has been demonstrated in a spin glass (SG) matrix. The ZFC-EB is suggested to originate from the unidirectional anisotropy formed isothermally along the FM/SG interface. For this typical physical system, both ways including the initial magnetization process and FC process could result in the unidirectional anisotropy. In addition, the training effect after ZFC is similar to those observed in conventional FC-EB systems. [ABSTRACT FROM AUTHOR]

We report a systematic study of the specific heat and dc magnetic susceptibility on the paramagnetic to ferrimagnetic transition (TC~141 K) in CuNMn3. A large magnetocaloric effect (MCE) at TC is observed with the entropy change of 3.49 J/kg K (6.38 J/kg K) for the field change of ΔH=20 kOe (45 kOe). The analysis of the isothermal magnetizations, including the derived Arrott plots and magnetic entropy change, shows a second-order like transition at TC. However, the existence of latent heat around TC is unambiguously manifested by the reduced slope of the temperature-time relaxations recorded during the specific heat measurement, indicating the transition is in fact weakly first-order in nature. The large MCE comparable with those observed the antiperovskite manganese carbides suggests it is equivalently interesting to explore the MCE in the antiperovskite manganese nitrides as in the carbides. [ABSTRACT FROM AUTHOR]