Complex magnetic properties of the rare-earth copper oxides, R sub 2 CuO sub 4 , observed via measurements of the dc and ac magnetization, EPR, microwave magnetoabsorption, and specific heat

Journal Article · Wed Jan 31 23:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.1934· OSTI ID:7172220

Oseroff, S B; Rao, D; Wright, F ^[1]; Vier, D C; Schultz, S ^[2]; Thompson, J D; Fisk, Z; Cheong, S; Hundley, M F ^[3]; Tovar, M ^[4]

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1. San Diego State University, San Diego, California 92182 (US)
2. University of California-San Diego, La Jolla, California 92093 (USA)
3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (USA)
4. Centro Atomico Bariloche 8400 Bariloche, Rio Negro, (Argentina)

We report the results of an extensive investigation of the magnetic properties of a large series of undoped {ital R}{sub 2}CuO{sub 4} single crystals with {ital R}==Pr, Nd, Sm, Eu, and Gd (which are the host compounds for the newly discovered series of electron cuprate superconductors) and mixture versions of the form {ital A}{sub 2{minus}{ital x}}B{sub x}CuO{sub 4}, with {ital A}==Pr, Nd, Sm, Eu, or Gd, and {ital B}==Gd, Tb, or Dy. We have measured dc and ac magnetization, microwave magnetoabsorption, EPR, and specific heat. These measurements reveal two characteristic transition temperatures associated with a novel complex magnetic behavior, including weak ferromagnetism, two sharp peaks in the low-field dc magnetization, an unusual anisotropy in the EPR resonance field for {ital R}=Gd, and two additional anisotropic microwave absorption modes. The higher characteristic transition temeperature at {similar to}270 K is associated with antiferromagnetic ordering of the Cu moments which are strongly coupled within the CuO{sub 2} layers. The lower, at {le}20 K, cannot be attributed to antiferromagnetic ordering of the {ital R} moments and is tentatively attributed to a spontaneous canted spin reorientation. An understanding of this magnetic behavior is important in order to ascertain its relationship to possible mechanisms of high-temperature superconductivity.

• OSTI ID: 7172220
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:4; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ANISOTROPY
ANTIFERROMAGNETISM
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL TEMPERATURE
CRYSTALS
ELECTRON SPIN RESONANCE
FERROMAGNETISM
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
MAGNETISM
MAGNETIZATION
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
RESONANCE
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE