Different Gd sup 3+ sites associated with magnetic ordering and structural distortions in Eu sub 2 CuO sub 4 :Gd sup 3+ observed via electron-paramagnetic-resonance measurements

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.9467· OSTI ID:6183724

Zysler, R D; Tovar, M ^[1]; Rettori, C; Rao, D; Shore, H; Oseroff, S B ^[2]; Vier, D C; Schultz, S ^[3]; Fisk, Z ^[4]; Cheong, S ^[5]

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1. Centro Atomico Bariloche and Instituto Balseiro, 8400 San Carlos de Bariloche, Rio Negro (Argentina)
2. Physics Department, San Diego State University, San Diego, California (USA)
3. Physics Department, University of California, San Diego, La Jolla, California (USA)
4. Los Alamos National Laboratory, Los Alamos, New Mexico (USA)
5. AT T Bell Laboratories, Murray Hill, New Jersey (USA)

We have measured the EPR spectrum of dilute Gd{sup 3+} ions substituting for Eu{sup 3+} in Eu{sub 2}CuO{sub 4}. Each one of the resonance lines shows a splitting into two or more weaker lines below {ital T}{sub {ital N}}{approx}215 K. The simultaneous appearance of a low-field microwave-absorption signal is attributed to the onset of long-range antiferromagnetic ordering with a weak ferromagnetic component. The splitting of the EPR spectrum is associated with different Gd sites in the magnetically ordered structure. A reduction of the local symmetry of the rare-earth sites below {ital T}{sub {ital N}} is described in terms of an internal magnetic field lying in the {ital ab} plane and additional crystal-field terms related to local crystallographic distortions. Dipolar and exchange contributions to the internal field are discussed. Possible random static displacements of the oxygen atoms in the CuO{sub 2} planes and their role in the development of the weak ferromagnetism and the presence of internal fields at the Gd sites are also analyzed. A strong dependence of the Gd EPR spectrum and the microwave absorption on the magnetic history of the samples has been observed, suggesting the formation of magnetic domains or a glassy state.

• OSTI ID: 6183724
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:17; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
CHALCOGENIDES
CHARGED PARTICLES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
CUPRATES
DEFORMATION
DOMAIN STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON SPIN RESONANCE
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
FERROMAGNETISM
GADOLINIUM IONS
IONS
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
MAGNETISM
ORDER PARAMETERS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
RESONANCE
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS