Structure and magnetic properties of LaMn{sub 1-x}Mg{sub x}O{sub 3} compounds

Journal Article · Wed Sep 01 00:00:00 EDT 2004 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.70.094426· OSTI ID:20664888

Blasco, J; Garcia, J; Subias, G; Sanchez, M C ^[1]

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1. Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, Consejo Superior de Investigaciones Cientificas y Universidad de Zaragoza, 50009 Zaragoza (Spain)

We substitute Mg for Mn in the LaMnO{sub 3} compound. LaMn{sub 1-x}Mg{sub x}O{sub 3} single phases can be formed up to x=0.5. Structural and electronic properties were studied by means of x-ray diffraction and x-ray absorption spectroscopy. A double perovskite is observed for x{>=}0.4 whereas no long Mn/Mg ordering is detected for x{<=}0.3. The former samples also show a structural transition from rhombohedral to monoclinic with decreasing temperature. The local structure around Mn evidences the absence of Jahn-Teller distortion since x=0.1. The samples with low Mg content have a ferromagnetic ground state while samples with x{>=}0.3 undergo a spin-glass transition at low temperatures. The frequency dependence of the freezing temperature follows a Vogel-Fulcher law and it is similar to canonical spin-glasses. The high temperature ac susceptibility of all samples obeys the Curie-Weiss law but the effective paramagnetic moments do not agree with a spin-only contribution for x{<=}0.4. Finally, we have demonstrated that Mg does not replace La in the perovskite lattice by studying selected La{sub 1-x}Mg{sub x}MnO{sub 3} samples. It always enters onto the perovskite B-site.

• OSTI ID: 20664888
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 70, Issue 9; Other Information: DOI: 10.1103/PhysRevB.70.094426; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
CURIE-WEISS LAW
FERROMAGNETIC MATERIALS
FREEZING
FREQUENCY DEPENDENCE
GROUND STATES
LANTHANUM COMPOUNDS
MAGNETIC SUSCEPTIBILITY
MANGANATES
MONOCLINIC LATTICES
PARAMAGNETISM
PEROVSKITE
SPIN GLASS STATE
TRIGONAL LATTICES
X-RAY DIFFRACTION
X-RAY SPECTRA
X-RAY SPECTROSCOPY