Structural and magnetic heterogeneities, phase transitions, and magnetoresistance and magnetoresonance properties of the composition ceramic La{sub 0.7}Pb{sub 0.3-x}Sn{sub x}MnO{sub 3}

Journal Article · Thu Mar 15 00:00:00 EDT 2012 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776112030193· OSTI ID:22027897

Pashchenko, A V; Prokopenko, V K; Revenko, Yu F; Burkhovetskii, V V; Shemyakov, A A ^[1]; Sil'cheva, A G ^[2]; Levchenko, G G ^[1]

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1. National Academy of Sciences of Ukraine, Galkin Institute for Physics and Engineering (Ukraine)
2. Luhansk Taras Shevchenko National University (Ukraine)

The La{sub 0.7}Pb{sub 0.3-x}Sn{sub x}MnO{sub 3} composition ceramic is studied by X-ray diffraction, resistive, magnetic, electron-microscopic, magnetoresistance, and NMR ({sup 55}Mn, {sup 139}La) methods. The substitution of tin for lead results in structural phase separation into the basic perovskite (R3-bar c) and spinell (Fd3m), phases: La{sub 0.7}Pb{sub 0.3-x}Sn{sub x}MnO{sub 3} {yields} La{sub 0.7-x}Pb{sub 0.3-x}MnO{sub 3} + 0.5xLa{sub 2}Sn{sub 2}O{sub 7}. Changes in the lattice parameter of the basic perovskite R3-bar c structure, the electrical resistivity, and the magnetic and magnetoresistance properties are caused by changes in the composition and content of a conducting perovskite ferromagnetic phase, the Mn{sup 3+}/Mn{sup 4+} ratio, and the imperfection of vacancy and cluster types. An in-plane nanostructured cluster is formed by Mn{sup 2+} ions located in distorted A-positions. The detected anomalous magnetic hysteresis is induced by the appearance of a unidirectional exchange anisotropy at the boundary of an in-plane antifer-romagnetic cluster coherently joined with a ferromagnetic matrix structure. The broad asymmetric NMR spectra of {sup 55}Mn and {sup 139}La indicate a high-frequency Mn{sup 3+} {r_reversible} Mn{sup 4+} superexchange and a nonuniform distribution of ions and defects. The constructed phase diagram characterizes a strong relation between the magnetic and transport properties in rare-earth manganites.

• OSTI ID: 22027897
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 114, Issue 3; Other Information: Copyright (c) 2012 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ANISOTROPY
CUBIC LATTICES
FERROMAGNETISM
LANTHANUM 139
LANTHANUM COMPOUNDS
LATTICE PARAMETERS
LEAD COMPOUNDS
MAGNETORESISTANCE
MANGANATES
MANGANESE 55
MANGANESE IONS
NANOSTRUCTURES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
TIN COMPOUNDS
TRIGONAL LATTICES
VACANCIES
X-RAY DIFFRACTION