Direct measurement of the magnetocaloric effect in La0.67Ca0.33MnO3

Review of the magnetocaloric effect in manganite materials

“…This discrepancy could arise from the differences in the sample processing routes and/or from the differently chemical composition. In fact, La 0.67 Ca 0.33 MnO 3 was found to show the largest MCE among the compositions investigated [32][33][34]. Lin et al [34] measured the MCE of La 0.67 Ca 0.33 MnO 3 and found the DT ad of 2.4 K for DH ¼ 2:02 T. This value of DT ad is smaller than that of Gd.…”

“…In fact, La 0.67 Ca 0.33 MnO 3 was found to show the largest MCE among the compositions investigated [32][33][34]. Lin et al [34] measured the MCE of La 0.67 Ca 0.33 MnO 3 and found the DT ad of 2.4 K for DH ¼ 2:02 T. This value of DT ad is smaller than that of Gd. It was suggested that the large magnetic entropy change was produced by the abrupt jump in magnetization that is associated with a first-order magnetic phase transition [32,33].…”

“…La 1Àx Ca x MnO 3 phases exhibited the largest MCEs among the existing manganites, but their Curie temperatures are quite below room temperature, for example, the maximum T C ¼ 267 K for La 0.67 Ca 0.33 MnO 3 [29][30][31][32][33][34]. This probably limits the usage of La 1Àx Ca x MnO 3 materials for AMR in the room-temperature range.…”

Effect of non-stoichiometry on the structural, magnetic and magnetocaloric properties of La0.67Ca0.33Mn1+δO3 manganites

“…Guo et al reported that the manganites with x = 0.2, 0.25 and 0.33 show maximum isothermal entropy changes (ΔS T ) of -5.5 J/kg·K at T C = 230 K, -4.7 J/kg·K at T C = 224 K and -4.3 J/kg·K at T C = 260 K, respectively, for a magnetic field change of 1.5 T [6]. The ΔS T values are higher than that of Gd for the same field change, however, the adiabatic temperature change (ΔT ad = 2.4 K for a field change of 2.02 T) is smaller than that of Gd [11].…”

A detailed study of the hysteresis in La0.67Ca0.33MnO3

“…An interesting example is the La-manganites, in particular La 0.67 Ca 0.33 MnO 3 which has been investigated for several years as a possible material for magnetocaloric applications [1][2][3]. Of particular interest is whether the phase transition is of first order or of second order.…”