Electronic, steric, and dilution effects on the magnetic properties of Sm2xMxCuO4y (M=Ce, Y, La, and Sr): Implications for magnetic pair breaking

B. Jiang, B.-H. O, and J. T. Markert
Phys. Rev. B 45, 2311 – Published 1 February 1992
PDFExport Citation

Abstract

Recent data suggest that the high-Tc compound Sm2xCexCuO4y presents considerable difficulties for conventional theories of magnetic pair breaking. We report results of x-ray diffraction, superconducting-quantum-interference-device magnetization, and resistivity measurements for single-phased polycrystalline specimens of Sm2xMxCuO4y (M=Ce, Y, La, and Sr) for various x and y. In each case, the magnetic Sm3+ ions are diluted by a nonmagnetic species: isovalent Y3+ and La3+, or nonisovalent Ce4+ and Sr2+. Rare-earth magnetic order occurs below 6 K in Sm2CuO4; isovalent dilution with M=Y results in a depression of the Néel temperature TN at an initial rate (1/TN0)(dTN/dx)=-0.0110/at. %, a result that can be well described by a simple theory of magnetic dilution. Isovalent dilution with M=La reveals a small steric effect. Nonisovalent dilutions are interpreted in terms of concentration-dependent exchange interactions; electron and hole dopings result in depression and enhancement of the rare-earth exchange coupling, respectively. Our results (scrj≲6 meV) indicate that the coupling between rare-earth ions and superconducting electrons is probably much smaller than previously suggested, and that conventional magnetic pair-breaking theory adequately describes these materials. Some magnetic features suggestive of a subtle transition in the range x=0.10–0.15 in the insulating M=Ce series are also observed.

  • Received 1 August 1991

DOI:https://doi.org/10.1103/PhysRevB.45.2311

©1992 American Physical Society

Authors & Affiliations

B. Jiang, B.-H. O, and J. T. Markert

  • Department of Physics, University of Texas, Austin, Texas 78712

References (Subscription Required)

Click to Expand
Issue

Vol. 45, Iss. 5 — 1 February 1992

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×