User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse




Journal Article

A comparison of high-Tc superconductors: Specific heat in magnetic fields at very low temperatures

There are no MPG-Authors available
External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available

Caspary, R., Winkelmann, M., & Steglich, F. (1989). A comparison of high-Tc superconductors: Specific heat in magnetic fields at very low temperatures. Zeitschrift für Physik B, 77(1), 41-45. doi:10.1007/BF01313617.

Cite as: http://hdl.handle.net/11858/00-001M-0000-0019-D4DE-8
We discuss specific-heat,C(T), results on YBa2Cu3O7−δ(δ=0.13, 0.99) and Bi2Sr2CaCu2O8. For completion, we compare these with literature data on La1.85Sr0.15CuO4 and La2CuO4 by emphasizing the data at lowest temperatures,T≦0.45K. The strong upturn inC(T)/T found atB=0 is predominantly associated with a splitting of nuclear states by quadrupolar interactions. The shift of this upturn towards higher temperatures, when magnetic fields up to 8 T are applied, indicates additional hyperfine splitting. For YBa2Cu3O6.87 and Bi2Sr2CaCu2O8, subtraction of the nuclear specific heat from the raw data reveals a spin-glass derived contribution γ*(T,B), with γ* being strongly depressed upon both warming and applying externalB-fields. The probable source for γ* T are impurity phases (in YBa2Cu3O7−δ) and/or frustrated Cu2+ moments created by lattice defects. Any intrinsic linear specific heat, γ i , due to, e.g., spinon excitations or normal electronic carriers, would have to imply γ i <1 mJ/K2 molef.u. for each of these two compounds.