Collapse of the vortex-lattice inductance and shear modulus at the melting transition in untwinned $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_7$

Abstract

The complex resistivity $\hat{\rho }(\omega )$ of the vortex lattice in an untwinned crystal of 93-K $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_7$ has been measured at frequencies $\omega /2\pi$ from 100 kHz to 20 MHz in a 2-Tesla field $\mathbf{H}\parallel \mathbf{c}$, using a 4-probe RF transmission technique that enables continuous measurements versus $\omega$ and temperature $T$. As $T$ is increased, the inductance ${\mathcal{L}}_s(\omega )=\mathrm{Im}\hat{\rho }(\omega )/\omega$ increases steeply to a cusp at the melting temperature $T_m$, and then undergoes a steep collapse consistent with vanishing of the shear modulus $c_{66}$. 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 ${\rho }_1(\omega )$ over 2 decades in $\omega$. Values of the pinning parameter $\kappa$ and shear modulus $c_{66}$ obtained show that $c_{66}$ collapses by over 4 decades at $T_m$, whereas $\kappa$ remains finite.

11 pages, 8 figures, Phys. Rev. B, in press

Cited by in corpus (3)

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• Comment to the paper : Collapse of the vortex-lattice inductance and shear modulus at the melting transition in untwinned YBa${}_2$Cu${}_3$O${}_7$, by Matl \QTR{em}{et al.}