Heat capacity data of doped NdBa[sub 2]Cu[sub 3]O[sub [ital x]]

Journal Article · Sat May 15 04:00:00 EDT 1993 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.352685· OSTI ID:6891818

Allenspach, P; Lee, B W; Gajewski, D; Maple, M B ^[1]; Yoo, S I; Kramer, M J ^[2]

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1. Department of Physics and Institute for Pure and Applied Physical Sciences, University of California-San Diego, La Jolla, California 92093 (United States)
2. Ames Laboratory, Iowa State University, Ames, Iowa 50011-3020 (United States)

Low-temperature specific-heat measurements were performed between 0.4 and 4 K on Nd--Ba--Cu--O-samples doped with Ca and additional Nd. In these samples, the specific-heat anomaly due to magnetic ordering of the Nd[sup 3+] ions as a function of hole concentration behaves similarly to that of oxygen-deficient NdBa[sub 2]Cu[sub 3]O[sub [ital x]]. In samples with 0[lt][ital T][sub [ital c]][lt]70 K, a broad anomaly due to short range magnetic interaction was found but no indication for long range magnetic ordering could be observed. In the semiconducting samples, 3D-Ising-like anomalies with [ital T][sub [ital N]] around 1.6 K were measured. In order to explain the behavior of the magnetic anomaly in the oxygen-deficient undoped samples, one could assume that the magnetic interaction depends on lattice parameters or interatomic distances. Our newest results clearly show, however, that the position and shape of the anomaly is mainly controlled by the density of carriers in the superconducting CuO[sub 2] planes, and not by structural properties. Thus, the magnetic rare-earth ions are isolated enough from the CuO[sub 2] planes not to influence superconductivity (except for Pr), but are not totally decoupled from the rest of the unit cell and the carrier concentration.

• OSTI ID: 6891818
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 73:10; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM ADDITIONS
CALCIUM ALLOYS
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DISPERSIONS
HIGH-TC SUPERCONDUCTORS
MAGNETIC PROPERTIES
MIXTURES
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SPECIFIC HEAT
SUPERCONDUCTORS
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS