Magnetic localization in mixed-valence manganites

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.8067· OSTI ID:534474

Viret, M; Ranno, L; Coey, J M ^[1]

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1. Physics Department, Trinity College, Dublin 2 (Ireland)

The metal-insulator transition is mixed-valence manganites of the (La{sub 0.7}Ca{sub 0.3})MnO{sub 3} type is ascribed to a modification of the spin-dependent potential J{sub H}{bold s{center_dot}S} associated with the onset of magnetic order at T{sub C}. Here J{sub H} is the on-site Hund`s-rule exchange coupling of an e{sub g} electron with s=1/2 to the t{sub 2g} ion core with S=3/2. Above T{sub C}, the e{sub g} electrons are localized by the random spin-dependent potential and conduction is by variable-range hopping. Over the whole temperature range, the resistivity varies as ln({rho}/{rho}{sub {infinity}})=[T{sub 0}{l_brace}1{minus}(M/M{sub S}){sup 2}{r_brace}/T]{sup 1/4}, where M/M{sub S} is the reduced magnetization. The temperature and field dependence of the resistivity deduced from the molecular-field theory of the magnetization reproduces the experimental data over a wide range of temperature and field. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 534474
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 13 Vol. 55; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM OXIDES
CURIE POINT
EXCHANGE INTERACTIONS
FERROMAGNETIC MATERIALS
LANTHANUM OXIDES
MAGNETIZATION
MANGANESE OXIDES
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
TRANSITION TEMPERATURE