Magnetocaloric effect in La1−xSrxMnO3 for x=0.13 and 0.16

Abstract

Magnetization of polycrystalline La1−xSrxMnO3 samples with x=0.13 and x=0.16 has been measured as a function of temperature and external magnetic field. Using the gathered data and the thermodynamic Maxwell’s relation, changes of the magnetic contribution to entropy under influence of the magnetic field, allowing to estimate the value of magnetocaloric effect, have been determined. The changes reach ∼7 J/(kg K) in the field of 7 T, which makes the studied samples good candidates for application for magnetic refrigeration. Expressions describing entropy and its change under influence of magnetic field have been derived in the molecular field approximation. Satisfactory agreement between the theoretical curves and the experimental dependencies has been found.

Magnetic entropy change in polycrystalline La1−xKxMnO3 perovskites

“…The simultaneous magnetic transition and discontinuous volume variation at T C strongly influences the magnetic entropy change [13,14] and such change is reported to be comparable with other solid magnetic refrigerants [3,7,15,16]. Manganites are advantageous because of their higher chemical stability, lower eddy current heating due to higher resistivity, inexpensive and tunable T C [17][18][19][20]. Therefore, a refrigeration unit composed of several manganites with different T C can be spanned over a wide range of temperature (viz., 260-340 K).…”

Magnetic entropy change in La0.67−Ca0.33MnO3

“…The ABO 3 -type perovskite manganese oxides have attracted much attention not only for their colossal magnetoresistance (CMR) effects but also for the large magnetocaloric effects [1][2][3][4]. The Curie temperature of this kind of material is related to the average size of cations in A positions r A and the mean manganese valence V Mn .…”

Crystal structure, magnetic and magnetocaloric properties of aluminum-doped La0.6Sr0.4MnO3 perovskites

“…The Srdoped La 1-x Sr x MnO 3 is a typical system exhibiting a large MCE during the transition from ferromagnetic to paramagnetic phase. For the La 1-x Sr x MnO 3 manganites, the Curie temperature is tunable between 197 and 370 K when the Sr concentration changes between 0.13 and 0.33 [8][9][10][11].…”

“…The inset shows the collapse of the experimental data onto the average curve; the solid line is the fit to Eq (9). …”