Excellent magnetocaloric properties of La0.7Ca0.3−xSrxMnO3(0.05⩽x⩽0.25) single crystals

Abstract

This letter reports on the superior magnetocaloric properties of La0.7Ca0.3−xSrxMnO3 (x=0.05, 0.10, 0.20, and 0.25) single crystals. Upon 50 kOe applied field, the magnetic entropy changes (ΔSM) reach values of ∼10.5, 7.45, 6.97, and 6.86J∕kgK for x=0.05, 0.10, 0.20, and 0.25 compositions, respectively. The large magnetic entropy changes have been found to occur around 300 K, thus allowing magnetic refrigeration at room temperature. Due to the absence of grains in the single crystals, the ΔSM distribution here is much more uniform than that of gadolinium and polycrystalline manganites, which is desirable for an Ericson-cycle magnetic refrigerator. The single crystals have the large magnetic entropy changes induced by low magnetic field change, which is beneficial for the household application of active magnetic refrigerant (AMR) materials. These results indicate that the present single crystals are excellent candidates as working materials for AMR.

Investigation of the critical behavior in Mn0.94Nb0.06CoGe alloy by using the field dependence of magnetic entropy change

“…Typical representative materials include Gd 5 (Si 1Àx Ge x ) 4 7 and Ni-Mn-Ga. 8 Perovskite manganites are also considered to be promising candidate for the magnetic refrigeration. [9][10][11] Since the magnetic properties of perovskite manganites, Curie temperature and saturation magnetization, are strongly doping-dependent, these typical materials are believed to be good candidates for magnetic refrigeration at various temperatures. 12,13 However, for different reasons, none of these materials have yet been employed in a commercial refrigerator.…”

Observance of Improved Magneto-resistance and Magnetic Entropy Change in La0.7(Ca0.2Sr0.1)MnO3:Pd Composite

“…The temperature dependence of the magnetic entropy change is shown in Fig. 7 [5,10,15]. These low field entropy values are also much higher when compared to manganites reported in the literature [5,14,16].…”

“…Considerable improvement in both the magnetic (MR) and magneto-caloric (MCE) properties of the pristine La 0.7 (Ca 0.2 Sr 0.1 )MnO 3 (LCSMO) has been observed with PdO addition. The maximum MR of 12.9 % (1 T) and 19.6 % (2 T) has been observed close to its T c (309 K) in the pristine LCSMO which The maximum values of magnetic entropy change | S M | of 11.7 J kg −1 K −1 (H = 3 T), 8.2 J kg −1 K −1 (H = 2 T) and 4.4 J kg −1 K −1 (H = 1 T) for LCSMO:Pd10 are found to be much higher than in the LCSMO single crystal and the corresponding LCSMO:Ag composite reported earlier [10,15]. LCSMO:Pd composite material possessing a sizable MR and high magnetic entropy value therefore shows an excellent possibility of a potential magnetic sensor and magnetic refrigerant close to room temperature.…”

“…Several manganite materials like LCBMO, LCSMO, PBMO and their composites with Ag 2 O and PdO have been investigated to explore their potential for magnetic sensing applications [8][9][10][11][12][13]. Besides, manganites have also shown good potential as active magnetic refrigerant (AMR) near room temperature [10,[14][15][16][17].…”

“…Thus we can expect to obtain enhanced properties in the composite material. Various manganite composites have been investigated for their efficacy towards magnetic sensing and refrigeration applications [8][9][10][11][12][13][14][15][16][17] 3 and MnO 2 (all with 5 N purity). These ingredients were ground thoroughly, calcined at several steps of 900 • C for 18 h, 1100 • C for 18 h, 1300 • C for 18 h, respectively, and finally sintered at 1400 • C. Thus prepared sample was powdered and PdO was added and pelletized.…”