Influence of structural disorder on magnetic and transport properties of (La0.7Sr0.3)0.5(Pr0.65Ca0.35)0.5MnO3 films
DOI (Low Temperature Physics):
https://doi.org/10.1063/1.1820566Ключові слова:
PACS: 71.30. h, 75.47.Gk, 75.47.LxАнотація
Magnetic and transport properties of (La0.7Sr0.3)0.5(Pr0.65Ca0.35)0.5MnO3) films prepared by a «co-deposition» utilizing the laser-ablation technique are investigated in a wide temperature range. The film deposited at 300˚C has a nano-crystalline disordered structure and exhibits a paramagnetic temperature dependence of the magnetization with a narrow peak (DT ≃ 10 K) at TG ≃ 45 K, which can be interpreted as a paramagnetic → superparamagnetic transition. A short-term annealing of the as-deposited film at 750 ˚C leads to the formation of a high-textured polycrystalline microstructure and to the appearance of ferromagnetic (FM) and metal—insulator (MI) transitions at TC ≃ 240 K and TP ≃ 140 K, respectively. The observed discrepancy between TP and TC values can be ascribed to a percolating nature of the MI transition, with an exponent of 5.3 for the percolating conductivity. The film deposited at Tsub ≃ 740 ˚C is composed of the lattice strain-free and the lattice-strained crystallites with different lattice parameters and TC‘s, and is consistently described in the framework of the Millis model [A.J. Millis, T. Darling, and A. Migliori, J. Appl. Phys. 83, 1588 (1998)]. For a single-phase crystalline film obtain TC ≃ 270 K and TP ≃ 260 K.
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Опубліковано
2004-12-29
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V.G. Prokhorov, V.S. Flis, G.G. Kaminsky, Y.P. Lee, J.S. Park, and V.L. Svetchnikov, Influence of structural disorder on magnetic and transport properties of (La0.7Sr0.3)0.5(Pr0.65Ca0.35)0.5MnO3 films, Low Temp. Phys. 31, (2004) [Fiz. Nizk. Temp. 31, 213-221, (2004)] DOI: https://doi.org/10.1063/1.1820566.
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Низькотемпературний магнетизм
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