Crystal structures and magnetic order of La{sub 0.5+{delta}} A{sub 0.5-{delta}}Mn{sub 0.5+{epsilon}}Ru{sub 0.5-{epsilon}}O{sub 3} (A=Ca,Sr,Ba): Possible orbital glass ferromagnetic state

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

DOI:https://doi.org/10.1103/PhysRevB.70.214416· OSTI ID:20662260

Granado, E ^[1]; Huang, Q ^[2]; Lynn, J W ^[2]; Gopalakrishnan, J ^[3]; Ramesha, K ^[4]

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1. Instituto de Fisica 'Gleb Wataghin', UNICAMP, Caixa Postal 6165, Campinas, SP, CEP 13083-970 (Brazil)
2. NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
3. Center for Superconductivity Research, University of Maryland, College Park, Maryland 20742 (United States)
4. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India)

The crystallographic and magnetic properties of La{sub 0.5+{delta}}A{sub 0.5-{delta}}Mn{sub 0.5+{epsilon}}Ru{sub 0.5-{epsilon}}O{sub 3}= (A=Ca,Sr,Ba) were investigated by means of neutron powder diffraction. All studied samples show the orthorhombic perovskite crystal structure, space group Pnma, with regular (Mn,Ru)O{sub 6} octahedra and no chemical ordering of the Mn{sup 3+} and Ru{sup 4+} ions. Ferromagnetic spin structures were observed below T{sub c}{approx}200-250 K, with an average ordered moment of {approx}1.8-2.0{mu}{sub B}/(Mn,Ru). The observation of long-range ferromagnetism and the absence of orbital ordering are rationalized in terms of a strong Mn-Ru hybridization, which may freeze the orbital degree of freedom and broaden the e{sub g} valence band, leading to an orbital glass state with carrier-mediated ferromagnetism.

• OSTI ID: 20662260
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 70, Issue 21; Other Information: DOI: 10.1103/PhysRevB.70.214416; (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
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CRYSTALLOGRAPHY
CUBIC LATTICES
DEGREES OF FREEDOM
FERROMAGNETIC MATERIALS
FERROMAGNETISM
GLASS
LANTHANUM COMPOUNDS
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MANGANESE COMPOUNDS
MANGANESE IONS
NEUTRON DIFFRACTION
ORTHORHOMBIC LATTICES
RUTHENIUM IONS
SPACE GROUPS
SPIN
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0065-0273 K