Magnetic order in RBa/sub 2/Cu/sub 2/O/sub 6+//sub x/ (invited)

Journal Article · Tue Nov 15 04:00:00 EST 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.342124· OSTI ID:6749307

Lynn, J W; Li, W

Neutron scattering results on the RBa/sub 2/ Cu/sub 3/ O/sub 6+//sub x/ (R = rare earth) class of systems are reviewed. For the oxygen-deficient systems (x<0.5), which are semiconducting, the Cu ions are observed to order with Neel temperatures as high as 500 K. The magnetic structure consists of strong nearest-neighbor antiferromagnetic couplings of the Cu spins within the Cu-O/sub 2/ layers, while nearest-neighbor spins in adjacent layers are also aligned antiferromagnetically. The moments are constrained in the tetragonal plane. At lower temperatures the Cu moments in the oxygen-deficient ''chain'' layers also order antiferromagnetically, with a moment that can be quite substantial (approx. 1/2 ..mu../sub B/). Both transition temperatures are very sensitive to the oxygen concentration. The magnetic heavy rare-earth compounds, on the other hand, order antiferromagnetically at very low temperatures, analogous to the ''conventional'' magnetic-superconductor systems such as RMo/sub 6/ S/sub 8/ and RRh/sub 4/ B/sub 4/. The ordering is not very sensitive to the oxygen concentration, and the antiferromagnetic state coexists with superconductivity. Differences in the ordering behavior are ascribed to crystal-field effects, which are briefly discussed. Finally, small-angle neutron scattering results in the vicinity of the superconducting transition temperature are also discussed.

• Research Organization: Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742, and National Bureau of Standards, Gaithersburg, Maryland 20899
• OSTI ID: 6749307
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 64:10; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
&amp; Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ANTIFERROMAGNETISM
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
COUPLING
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON PAIRS
INTERMEDIATE COUPLING
J-J COUPLING
MAGNETISM
NEEL TEMPERATURE
NEUTRON DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE