Microwave Properties of Ba(0.6)K(0.4)BiO(3) Crystals

TL;DR

This study investigates the microwave surface resistance of Ba(0.6)K(0.4)BiO(3) crystals under magnetic fields, analyzing energy losses and vortex dynamics to understand its superconducting properties.

Contribution

It provides the first detailed analysis of microwave surface resistance and vortex pinning in Ba(0.6)K(0.4)BiO(3) crystals using the Coffey and Clem model.

Findings

Pinning energy is weaker than in cuprate superconductors.

Temperature dependence of the first-penetration and upper critical fields was determined.

Depinning frequency was characterized across the temperature range.

Abstract

We report on field-induced variations of the microwave surface resistance at 9.6 GHz of Ba(0.6)K(0.4)BiO(3) crystals. Energy losses have been investigated as a function of the static magnetic field in the range of temperatures 4.2 K - Tc. By analyzing the experimental results in the framework of the Coffey and Clem model we determine the temperature dependence of the first-penetration field, upper critical field and depinning frequency. The results show that the pinning energy of this bismuthate superconductor is weaker than those of cuprates.