Suppression of the superconducting transition temperature {ital T}{sub {ital c}} around {ital x}{approximately}0.115 in La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4}
- Institute for Materials Research, Tohoku University, Sendai 980 (Japan)
Detailed studies of the superconducting diamagnetism of La{sub 2{minus}{ital x}{minus}{ital y}}Nd{sub {ital y}}Sr{sub {ital x}}CuO{sub 4} show that the characteristic concentration {ital x}{sub dip} at which the largest {ital T}{sub {ital c}} suppression is observed changes from 0.115 to 0.125 on Nd doping around {ital y}{approximately}0.12, above which the structural transition to the low-temperature tetragonal (LTT) phase is observed. This indicates that also in La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4}, the {ital x}{sub dip} value is, in principle, also 1/8 as in La{sub 2{minus}{ital x}}Ba{sub {ital x}}CuO{sub 4}. We propose that the largest {ital T}{sub {ital c}} suppression around {ital x}{approximately}0.115 in La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4} is the result of the existence of two competitive factors. One is the local distortion expanding the LTT region around the Sr{sup 2+} ion, which is largest at {ital x}=1/8 and acts to suppress {ital T}{sub {ital c}}. The other is the antiferromagnetic spin fluctuation energy, which might increase with {ital x} and acts to increase {ital T}{sub {ital c}}. On Nd doping, the former factor becomes larger around {ital x}=0.125 than around {ital x}=0.115 and the {ital x}{sub dip} value moves to 0.125. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 283873
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 53, Issue 17; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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