Tunable magnetocaloric effect near room temperature in La0.7-xPrxSr0.3MnO3 (0.02 ≤ x ≤ 0.30) manganites

Abstract

We have systematically investigated the compositional dependence of the magnetic and magnetocaloric properties of La0.7-xPrxSr0.3MnO3 (LPSMO). Polycrystalline samples of LPSMO with 0.02 ≤ x ≤ 0.30 were prepared by a standard solid-state reaction method with phase purity and structure confirmed using x-ray diffraction. Temperature dependent magnetization measurements and Arrott analysis reveal second order ferromagnetic transitions in each sample with Curie temperature decreasing progressively with increasing Pr content from ∼350 K for x = 0.02 to ∼295 K for x = 0.30. Magnetic entropy change (ΔSM) was calculated by applying the thermodynamic Maxwell equation to a series of isothermal field dependent magnetization curves. In the sample with x = 0.30, the maximum value of −ΔSM reaches ∼2.08 J/kg K at 295 K for a field change of 1.5 T. Reduced Pr content corresponds to larger values of entropy change, reaching −ΔSM ∼2.79 J/kg K for the x = 0.02 doping. The refrigeration capacity for each composition reached sizable values of 33–48 J/kg for a small applied field of 1.5 T.

Tunable spin reorientation transition and magnetocaloric effect in Sm0.7−xLaxSr0.3MnO3 series

“…We compute RC using the equation, The magnetocaloric parameters of all the samples are listed in Table 2. We compare the magnetocaloric parameters of samples with T c around room temperature reported in literature 18,19,20,21 along with our samples in Table 3. …”

“…11,12,29,30,31 Borges et al 18 interpreted that the cusp is due to increase of coercive field with lowering temperature. However, the coercive field of x= 0.6 sample is only 120 Oe even at 10 K, which indicates that the origin of the low temperature anomaly is not due to increase in coercive field.…”

“…are also considered to be one of the potential materials for magnetic refrigeration. 5,6,7,8,9 Very recently, C. …”

The influence of disorder on magnetocaloric effect and the order of transition in ferromagnetic manganite (La1−x Nd x )2/3(Ca1−y Sr y )1/3MnO3

“…Recently, the influence of the first-order and the secondorder phase transitions on the MCE and its universality has been well studied in several manganites [47][48][49][50]. The purpose of this work is that the quenched chemical disorder suppressed the first-order magnetic phase transitions in ferromagnetic manganites, which have important consequences on the physical properties of these materials.…”

Magnetic and magnetocaloric properties of nanocrystalline La 0.5 Sr 0.5 MnO 3

“…Many other materials such as Laves phases LaFe 13−x Si x [12] and NiMn-based heusler alloys [13,14]are also being increasingly investigated for magnetic refrigeration. Besides, with the report of large MCE observed in the hole-doped perovskite manganite [15][16][17][18], this material is also expected to be one of the most promising materials since its Curie temperature and magnetic phase transition are strongly doping dependent and the magnetic refrigeration can be realized at various temperatures. [19,20] The perovskite manganites with the form Ln 1−x A x MnO 3 (Ln=rare earth element, A=divalent alkaline earth element) have been the subject of intense investigation in recent years due to their fascinating properties arising from spin-balance sensitivity, orbital contribution, lattice distortion and charge degrees of freedom [21][22][23][24].…”