Pulsed-magnetic-field measurements of Hall potential oscillations in $\alpha -(\mathrm{BEDT}-\mathrm{TTF}{)}_2\mathrm{TlHg}(\mathrm{SCN}{)}_4$ within the quantum Hall regime

Using a variant of the Corbino geometry in pulsed magnetic fields of up to 60 T, we have made direct measurements of the Hall potential in $\alpha -(\mathrm{BEDT}-\mathrm{TTF}{)}_2\mathrm{TlHg}(\mathrm{SCN}{)}_4$ within the quantum Hall regime. This method enables the in-plane components of the resistivity tensor, which are normally very difficult to measure, to be investigated and the nonlinear behavior of the sample’s $I-V$ characteristics to be studied. It is found that an increasing probability of magnetic breakdown at higher fields leads to a degradation of the quantum Hall effect.