The complex resistivity ρ(ω) of the vortex lattice in an untwinned crystal of 93-K YBa2Cu3O7 has been measured at frequencies ω/2π from 100 kHz to 20 MHz in a 2-T field H∥c, using a four-probe rf transmission technique that enables continuous measurements versus ω and temperature T. As T is increased, the inductance Ls(ω) = Imρ(ω)/ω increases steeply to a cusp at the melting temperature Tm, and then undergoes a steep collapse consistent with vanishing of the shear modulus c66. We discuss in detail the separation of the vortex-lattice inductance from the "volume" inductance, and other skin-depth effects. To analyze the spectra, we consider a weakly disordered lattice with a low pin density. Close fits are obtained to ρl(ω) over 2 decades in ω. Values of the pinning parameter κ and shear modulus c66 obtained show that c66 collapses by over 4 decades at Tm, whereas κ remains finite.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - Jun 1 2002
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics