磁制冷
铁磁性
材料科学
居里温度
绝热过程
凝聚态物理
等温过程
磁场
铁磁性
热容
磁化
热力学
大气温度范围
相变
物理
量子力学
作者
Raghda Abu Elnasr,Samy H. Aly,Sherif Yehia,Fatema Z. Mohammad
标识
DOI:10.1007/s10948-022-06298-2
摘要
Abstract We present a study on the magnetic properties and magnetocaloric effect (MCE) in R 3 Co 11 B 4 , where R = Pr, Nd, Tb, Dy, and Ho. The two-sublattice model is used for calculating magnetization, magnetic heat capacity, isothermal entropy change ∆S m , and adiabatic temperature change ∆T ad , for different magnetic field changes ∆H = 1.5, 3, and 5 T and at temperatures up to 600 K. Direct and inverse MCE are shown to take place in the ferrimagnetic compounds with R = Tb, Dy, and Ho. The maximum isothermal magnetic entropy change and maximum adiabatic temperature change have been calculated for ferromagnetic Nd 3 Co 11 B 4 compound to be 1.85 J/K mol and 6.5 K at T c = 432 K, for a field change ∆H = 5 T. The relative cooling power (RCP) is in the 44–161 J/mol range for the same field change. Also, the type of phase transition is investigated in the light of Arrott plots, universal curves, and the features of the temperature and field dependences of the magnetization, heat capacity, entropy, and the magnetocaloric properties. Those features confirm that the transition at the Curie temperature of these compounds is of the second order.
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