Transport and superconducting properties of rare earth magnetic superconductors
An investigation of transport and magnetic properties of two groups of magnetic superconductors, tetragonal RRh{sub 4}B{sub 4} and orthorhombic high-{Tc} oxides RBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, where R represents rare earth elements and Y, was carried out by means of electrical resistance and magnetic measurements. Significant influence of the magnetic anisotropy on the upper critical magnetic field H{sub C2} of the superconducting state was observed in RRh{sub 4}B{sub 4} with R = Y, Er, and Tm. Lower H{sub C2} values were observed for these compounds in the easy directions. Electrical resistance and magnetic measurements on polycrystalline RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} samples for R = Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu established almost identical superconducting transition temperatures {Tc} = 90 to 94 K for all these compounds (except for R = La which has {Tc} = 56 K), revealing apparent decoupling of the conduction electrons and the R magnetic ions. The upper critical magnetic fields H{sub C2} of these high-{Tc} oxides are estimated by the WHHM theory to be of the order of megaoersteds at 0 Kelvin. In the normal state, the susceptibility of these compounds can be fitted to the sum of a Curie-Weiss term and a temperature independent term. The temperature and magnetic field dependences of J{sub c} obtained by this model are consistent with those obtained from direct current-voltage measurements. Fine powders of RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} can be aligned in nonmagnetic epoxy by an applied magnetic field at room temperature due to the magnetic anisotropy of these compounds.
- Research Organization:
- California Univ., San Diego, CA (USA)
- OSTI ID:
- 5944221
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BORIDES
BORON COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL FIELD
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MONOCRYSTALS
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
RHODIUM BORIDES
RHODIUM COMPOUNDS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE