Transport and magnetic properties of polycrystalline Sm[sub 2[minus][ital x]]Ce[sub [ital x]]CuO[sub 4[minus][ital y]]

Journal Article · Sun May 15 00:00:00 EDT 1994 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.356849· OSTI ID:7274223

Jardim, R F; Westphal, C H; Cohenca, C H ^[1]; Ben-Dor, L ^[2]; Maple, M B ^[3]

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1. Instituto de Fisica, Universidade de Sao Paulo, CP 20516, 01498-970, Sao Paulo, SP (Brazil)
2. Department of Inorganic and Analytical Chemistry, Hebrew University, Jerusalem 91904 (Israel)
3. Department of Physics and Institute for Pure and Applied Physical Sciences, University of California at San Diego, La Jolla, California 92093-0019 (United States)

A systematic study of transport and magnetic properties of polycrystalline Sm[sub 2[minus][ital x]]Ce[sub [ital x]]CuO[sub 4[minus][ital y]] (0.15[le][ital x][much lt]0.18) specimens obtained from a sol-gel precursor reveals a striking double resistive superconducting transition. One of the resistive transitions takes place at a temperature [ital T][sub [ital ci]] and is almost insensitive to Ce concentration, applied magnetic field, and current density, while the other transition occurs at a lower temperature [ital T][sub [ital cj]] and is very sensitive to Ce content, applied magnetic field, and current density. Alternating-current magnetic susceptibility [chi][sub ac] measurements reveal two interesting features. There is only one contribution to the diamagnetic signal below [similar to]20 K, which is particularly evident in the resistive component [chi][double prime] of [chi][sub ac] where a peak at [ital T][sub [ital cj]] can be identified. The application of an applied magnetic field shifts the [chi][double prime] peak to lower temperatures and reveals a spin-glass-like behavior. All the results can be satisfactorily explained in terms of weakly linked Josephson junctions between small superconducting islands. The small islands have a superconducting transition at a higher temperature [ital T][sub [ital ci]], and the long-range phase coherence is achieved through Josephson coupling at lower temperatures [ital T][sub [ital cj]]. All the results suggest a superconducting glass state in a disordered Josephson network.

• DOE Contract Number: FG03-86ER45230
• OSTI ID: 7274223
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 75:10; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

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CERIUM OXIDES
CHALCOGENIDES
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SUPERCONDUCTING JUNCTIONS
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