Preparation and magnetic properties of LaMnO3 + δ (0 ≤ δ ≤ 0.154)

Autor: J. Salminen, P A Petrenko, Yu. P. Stepanov, V. N. Stamov, R. Laiho, V. S. Zakhvalinskiĭ, K. G. Lisunov, Erkki Lähderanta
Rok vydání: 2006
Předmět:
Zdroj: Physics of the Solid State. 48:2300-2309
ISSN: 1090-6460
1063-7834
DOI: 10.1134/s1063783406120109
Popis: The structural, electrical, and magnetic properties of ceramic perovskite manganites LaMnO3 + δ (δ = 0–0.154) are investigated. It is found that, in a weak magnetic field (B = 2 G), the LaMnO3 + δ manganite with δ = 0.065 at temperatures below the Curie temperature T C of the paramagnet-ferromagnet phase transition has a mixed (spin glass + ferromagnet) phase. In LaMnO3 + δ manganites with the parameter δ = 0.100–0.154, this phase transforms into a frustrated ferromagnetic phase. A similar transformation was observed previously in La1−x CaxMnO3 compounds at calcium contents in the range 0 ≤ x ≤ 0.3. This similarity is explained by the fact that, in both materials, the Mn4+ concentration and, accordingly, the hole concentration c change equally in the concentration range from ∼0.13 to 0.34 with an increase in x or δ. However, the magnetic irreversibility, the concentration dependences of the Curie temperature T C(c) and the magnetic susceptibility X(c), and the critical behavior of the temperature dependence of the susceptibility X(T) in the vicinity of the Curie temperature T C differ substantially for these two materials. The observed differences are associated with the distortion of the cubic perovskite structure, the decrease in the degree of lattice disorder, and a more uniform distribution of holes in the LaMnO3 + δ manganites as compared to the La1 − x CaxMnO3 compounds.
Databáze: OpenAIRE
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