Volume 81, Number 5, March 2008
Article Number 57007
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 19 February 2008
EPL, 81 (2008) 57007
DOI: 10.1209/0295-5075/81/57007

Doping dependence of the upper critical field in La2-xSrxCuO4 from specific heat

Y. Wang and H.-H. Wen

National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences - P.O. Box 603, Beijing 100080, PRC

received 29 October 2007; accepted in final form 15 January 2008; published March 2008
published online 19 February 2008

The low-temperature specific heat of La2-xSrxCuO4 (LSCO) single crystals in the magnetic field H up to 12 T has been examined over a wide range of doping (0.063$\leqslant$p$\leqslant$0.238). From this we have mapped the upper critical field Hc2 of LSCO across the entire superconducting diagram. It is found that the Hc2 shows a doping dependence similar to that of the critical temperature Tc. We have discussed the implications of the result and proposed that there may be an effective superconducting energy scale responsible for the Hc2 behavior in the underdoped region.

74.25.Bt - Thermodynamic properties.
74.25.Op - Mixed states, critical fields, and surface sheaths.
74.72.Dn - La-based cuprates.

© EPLA 2008