Specific heat of GdBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ in the normal and superconducting states

Journal Article · Sun Nov 01 00:00:00 EST 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.36.6915· OSTI ID:5798291

Reeves, M E; Citrin, D; Pazol, B G; Friedmann, T A; Ginsberg, D M

The specific heat c, resistance R, and magnetic susceptibility chi of the high-temperature superconductor GdBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ have been measured from 1.5 to 180 K and compared with those of YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ and La/sub 1.85/Ba/sub 0.15/CuO/sub 4/. For the Gd compound, an antiferromagnetic transition is seen in the specific-heat data at 2.24 K, and a Curie-Weiss dependence of chi is also seen, with 7.98 Bohr magnetons per Gd ion and 1/chi extrapolating to zero at -5.89 K. The entropy associated with this peak in the specific heat is consistent with an assignment of J = 7/2 to the total angular-momentum quantum number of the Gd ion, indicating that crystal-field effects are small. The specific heat of the Gd compound is larger than that of the Y compound at these temperatures; this is attributed to the larger mass of the Gd ion. A peak in c/T/sup 3/ near 20 K in the Gd compound indicates a sharply defined peak in the phonon density of states near 10 meV. The superconducting transition temperature T/sub c/ of GdBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ indicated by the specific-heat data is 93.8 K, and the jump in the specific heat at T/sub c/ is 301 mJ/K g-atom, in agreement with previous observations for YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/. Evidence is seen for a temperature-dependent phonon density of states in GdBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/, and it is pointed out that such a temperature dependence is also seen in previously published data for La/sub 1.85/Ba/sub -0.15/CuO/sub 4/ and La/sub 1.8/Sr/sub 0.2/CuO/sub 4/.

• Research Organization: Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801
• OSTI ID: 5798291
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 36:13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
MAGNETIC SUSCEPTIBILITY
SPECIFIC HEAT
SUPERCONDUCTIVITY
COPPER OXIDES
GADOLINIUM OXIDES
CURIE-WEISS LAW
EXPERIMENTAL DATA
LANTHANUM OXIDES
LOW TEMPERATURE
PHONONS
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
YTTRIUM OXIDES
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
GADOLINIUM COMPOUNDS
INFORMATION
LANTHANUM COMPOUNDS
MAGNETIC PROPERTIES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUASI PARTICLES
RARE EARTH COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties
656100 - Condensed Matter Physics- Superconductivity