Magnetic and resistive measurements of the superconducting critical fields of melt-cast ${\mathrm{Ba}}_{0.65}$${\mathrm{K}}_{0.35}$${\mathrm{BiO}}_3$

The upper and lower critical fields of a melt-cast polycrystalline sample of ${\mathrm{Ba}}_{0.65}$ ${\mathrm{K}}_{0.35}$ ${\mathrm{BiO}}_3$ synthesized by a novel technique are obtained from both resistive and magnetic measurements. The coherence length ${\xi }_{\mathrm{GL}}$, penetration depth ${\lambda }_{\mathrm{GL}}$, and Ginzburg-Landau parameter κ are determined and the size of the specific-heat jump is predicted. The estimated electron-phonon coupling parameter is about 1.