Effects of oxygen on the magnetic order of the rare earth ions in RBa[sub 2]Cu[sub 3]O[sub 6+x] (R = Dy, Er, and Nd)
Neutron scattering techniques have been used to study the effects of oxygen on the magnetic order of the rare earth ions in RBa[sub 2]Cu[sub 3]O[sub 6+x] (R = Dy, Er, Nd). For fully oxygenated superconducting (T[sub c] = 92 K) ErBa[sub 2]Cu[sub 3]O[sub 7] two-dimensional (2D) short range magnetic correlations grow as the ordering temperature T[sub N] = 0.62 K is approached from above, while at T[sub N] long range correlations develop in the a-b plane, which induce 3D long range order. Below T[sub N] the thermodynamic order parameter obeys Onsager's exact solution of the 2D S = 1/2 Ising model. For oxygen-reduced superconducting ErBa[sub 2]Cu[sub 3]O[sub 6.6] the 3D ordering temperature is lowered to T[sub N] [approx equal] 0.48 K. For fully de-oxygenated insulating ErBa[sub 2]Cu[sub 3]O[sub 6] down to the lowest temperature achieved (T = 60 mK) neither 2D or 3D long range order ever develop. For fully oxygenated superconducting DyBa[sub 2]Cu[sub 3]O[sub 7] (T[sub c] [approx equal] 92 K) 3D long range order occurs at T[sub N] [approx equal] 0.93 K. As the authors decrease the oxygen concentration in this material they see a concomitant decrease in the 3D magnetic ordering temperature. For their highest oxygenated superconducting NdBa[sub 2]Cu[sub 3]O[sub 6.94] (T[sub c] [approx equal] 92 K), 3D long range order develops below T[sub N] [approx equal] 0.53 K. For a small reduction of oxygen to x = 0.78, the authors observe drastic effects on the Nd order; 3D order is inhibited and only short range 2D correlations are found at low temperature. At (non-superconducting) x = 0.45, the 3D correlations are better developed at low temperature, yet long range order still does not occur. For x = 0.3, 3D long range order of the Nd ions is reestablished, developing below T[sub N] [approx equal] 1.5 K, three times that of the fully oxygenated material. The results demonstrate that the chain layer oxygen has a considerable influence on the rare earth magnetic order.
- Research Organization:
- Maryland Univ., College Park, MD (United States)
- OSTI ID:
- 7114752
- Country of Publication:
- United States
- Language:
- English
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Effects of oxygen on the magnetic order of the rare-earth ions in {ital R}Ba{sub 2}Cu{sub 3}O{sub 6+{ital x}} ({ital R}=Dy, Er, Nd)
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Related Subjects
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
COMPLEXES
CONCENTRATION RATIO
COPPER COMPOUNDS
CUPRATES
DIFFRACTION
DOMAIN STRUCTURE
DYSPROSIUM IONS
ELEMENTS
ERBIUM IONS
HIGH-TC SUPERCONDUCTORS
INTERMETALLIC COMPOUNDS
IONS
MAGNETIC PROPERTIES
NEODYMIUM IONS
NEUTRON DIFFRACTION
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPLEXES
SCATTERING
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE