Magnetocaloric behavior of rare earth doped La0.67Ba0.33MnO3

Na-doped La 0.7 Ca 0.3 MnO 3 compounds exhibiting a large magnetocaloric effect near room temperature

“…The value of T C thus increases with increasing Na content. A similar tendency towards high T C value with an increase < r A > has been also observed in the case of the substitution a large radius cation into A-site of LCMO, such as Ag + , K + , Sr 2+ , and Ba 2+ [2,[4][5][6][7][8]13], and in La 0.34 R 0.33 Ba 0.33 MnO 3 compounds with R=Pr, Nd, Sm, and Gd [14].…”

“…For 12 kOe, the value of ΔT max is found to be about 2.5, 1.0, and 0.8 K that takes place at T=259, 288, and 300 K for x=0, 0.05, and 0.1, respectively. These values are significantly higher than those reported for some Adoped manganites if compared in the same field change [14,16]. However, in comparing with Gd metal [27], these values are modest, but with advanced features such as easy to prepare, controllable T C , high chemical stability, low-cost, wide magnetic phase transition region, and high RCP value, La 0.7−x Na x Ca 0.3 MnO 3 compounds should be considered as a potential candidate for the Ericsoncycle magnetic refrigerator near the RT region.…”

“…2(b) for a representative sample x=0.05. According to a phenomenological model that can be used to predict about the magnetocaloric properties for some manganites [9,14,16], M(T) data can be described by…”

“…The temperature dependence of magnetic entropy change of a magnetic material under an applied magnetic field change from 0 to H can be calculated as following [9,14]. In order to understand more the nature of the FM-PM phase transition in the samples, we used the scaling of the magnetic entropy change method to construct their ΔS m (T)/ΔS max versus θ, where θ=(T-T C )/(T r -T C ) is the rescaled temperature and T r is the reference temperature [17].…”

“…Based on the phenomenological model, the change in the adiabatic temperature (ΔT) for the samples can be evaluated by using the equation [14,16]:…”