Rao, Ashok and Radheshyam, S and Kumar, Rajesh and Gupta, Sandeep and Meingast, C and Gahtori, Bhaskar and Agarwal, S K and Sivakumar, K M and Kuo, Y K (2007) The influence of Mn doping on the thermal expansion of the high TC superconductor YBa2(Cu1−xMnx)3Oy. Journal of Physics Condensed Matter, 19 (5).

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Abstract

Measurement of the linear thermal expansion α has been carried out for Mn substituted YBa2(Cu1−xMnx )3Oy (0 � x � 2%) using a high resolution dilatometer over the temperature range 10–300 K. Across the superconducting transition, the jump in the coefficient of linear thermal expansion �α was found to decrease with increasing Mn content. For the pure sample, we observed a negative jump. While a threefold decrease in �α with x = 0.5% was observed, only slight changes in the oxygen content and transition temperature have been noted, as a function of the Mn concentration. The above observations clearly suggest that the substituent Mn is being incorporated into the superconductors as a whole and not in the form of a local cluster. Further, from the Ehrenfest relations, the pressure dependence of TC (dTC/dP) and the discontinuity in the compressibility, �K, are expected to decrease with the Mn concentration

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