A-site K-doped lanthanum manganite nanocrystalline La0.67Ba0.33MnO3 for room-temperature micro-scale magnetic cooling

被引：2

作者：

Oumezzine, Marwene ^{[1
]}

Rostas, Arpad Mihai ^{[2
,3
]}

Bocirnea, Amelia Elena ^{[2
]}

Hlil, El Kebir ^{[4
]}

Galca, Aurelian Catalin ^{[2
]}

机构：

[1] Univ Monastir, Fac Sci Monastir, Lab Phys Chem Mat, Monastir 5019, Tunisia

[2] Natl Inst Mat Phys, Magurele 077125, Romania

[3] Natl Inst Isotop & Mol Technol, Cluj Napoca 400293, Romania

[4] Univ Grenoble Alpes, Inst Neel, CNRS, Grenoble INP, F-38000 Grenoble, France

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2024年 / 976卷

关键词：

Mixed -valence perovskite; Magnetocaloric effect; Magnetic transition; EPR spectroscopy; MAGNETOCALORIC PROPERTIES;

D O I：

10.1016/j.jallcom.2023.173257

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Bulk nanocrystalline La0.67Ba0.33_xKxMnO3 (with x = 0, 0.05, 0.1, and 0.2) manganites have been prepared by the modified sol-gel method (Pechini). The single-phase rhombohedral crystal structure with the R-3c (no. 167) space group was verified by X-ray diffraction (XRD) and sustained by Rietveld refinement. As follows from the results of XRD structural analyses, the increase in K-doping triggers an increase in the distortion of the MnO6 octahedra, which eventually causes the narrowing of the eg bandwidth. Mn is in a mixed valence state of Mn4+/ Mn3+ as inferred by X-ray photoelectron spectroscopy. Magnetic measurements confirm that the Curie tem-perature decreases from 348 K for La0.67Ba0.33MnO3 to 316 K for La0.67Ba0.13K0.20MnO3. The increasing of the Mn4+ ion concentration at the B-site sublattice and A-site ionic disorder (sigma 2) breaks up the double exchange interaction between the Mn3+ and Mn4+ ions. The ferromagnetic to paramagnetic second-order magnetic phase transition at TC is also confirmed by electron paramagnetic resonance. According to magnetic field-dependent magnetization isotherms at different temperatures, La0.67Ba0.13K0.20MnO3 shows a relatively large magneto -caloric effect (1400 mJ cm_ 3 K_ 1 at 316 K under 5 T applied magnetic field), which raises the possibility of using this material for room-temperature micro-scale magnetic cooling.

引用

页数：9