Influence of oxygen content on the structural, magnetotransport, and magnetic properties of LaMnO{sub 3+{delta}}

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.8902· OSTI ID:632635

Ritter, C ^[1]; Ibarra, M R; De Teresa, J M; Algarabel, P A; Marquina, C; Blasco, J; Garcia, J ^[2]; Oseroff, S ^[3]; Cheong, S ^[4]

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1. Institute Laue-Langevin, Boite Postale 156, 38042 Grenoble, Cedex (France)
2. Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza and Consejo Superior de Investigaciones Cientificas, Facultad de Ciencias, 50009-Zaragoza (Spain)
3. Physics Department, San Diego State University, San Diego, California 92108 (United States)
4. Bell Laboratories, Lucent Technologies, 700 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)

A systematic study of the effect of oxygen content on the structural, magnetotransport, and magnetic properties has been undertaken on a series of LaMnO{sub 3+{delta}} samples, with {delta}=0, 0.025, 0.07, 0.1, and 0.15. Measurements of the ac initial magnetic susceptibility, magnetization, magnetoresistance, and neutron diffraction, including small-angle neutron scattering (SANS), were performed in the temperature range 1{endash}320 K using high magnetic fields up to 12 T. The antiferromagnetic order found in LaMnO{sub 3} evolves towards a ferromagnetic order as {delta} increases. This behavior is accompanied by a drastic reduction of the static Jahn-Teller distortion of the MnO{sub 6} octahedra. The ferromagnetic coupling weakens for {delta}{ge}0.1. The magnetic behavior is interpreted by taking into account two effects caused by the increase in {delta}: cation vacancies and Mn{sup 4+}/Mn{sup 3+} ratio enhancement. The orthorhombic crystallographic structure becomes unstable at room temperature for {delta}{ge}0.1. The sample {delta}=0.1 shows a structural transition from rhombohedral to orthorhombic below T{sub S}{approx}300thinspK with a huge change in the cell volume. All the studied compounds were found to be insulating at low temperatures with no appreciable magnetoresistance, except for {delta}=0.15, in which we observed a large value for the magnetoresistance. The SANS results indicate that magnetic clustering effects are important below T{sub C} for {delta}{ge}0.07, which could explain the intriguing ferromagnetic insulator state. In the {delta}=0.07 and {delta}=0.10 samples we found at temperatures below T{sub C} magnetic and structural anomalies that are characteristic of charge ordering. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 632635
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 14 Vol. 56; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETIC MATERIALS
CHEMICAL COMPOSITION
CRYSTAL-PHASE TRANSFORMATIONS
JAHN-TELLER EFFECT
LANTHANUM OXIDES
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETIZATION
MAGNETORESISTANCE
MANGANESE OXIDES
NEUTRON DIFFRACTION
OXYGEN
STOICHIOMETRY
VACANCIES