Observation of Quantum Hall effect in GaAs/AlGaAs heterostructure at temperature dependence 4.2 K of Quantum Resistance Standard

This research examines the quantum Hall effect of a GaAs/AlGaAs heterostructure sample at the temperature of 4.2 K and measures the longitudinal Rxx and Hall resistance RH at $I = 10 \mu \mathrm{A}$. The corresponding Hall plateaus are represented by the depicted longitudinal Rxx and Hall resistance RH curves, however, the Hall resistance RH’s characteristics are not complete. The odd number’s plateau index i was not observed. At $i = 2$ and $i = 4$, the longitudinal resistance characteristic Rxx approaches zero. Comparing the measurement results at 1.5 K (theoretical) and 4.2 K, it was discovered that there were deviations of $1.5 \mathrm{m}\Omega / \Omega$ ($i = 2$) and $5 \mathrm{m}\Omega / \Omega (i =4)$, respectively. The effect of rising temperature is a factor contributing to the quantum Hall effect’s incompleteness. We can identify abnormalities while measuring or determining the time period of operation from the characteristics of the measured results. Moreover, the external magnetic field is measured around the Quantum Hall Resistance (QHR) standard system. It will be able to securely evaluate the effects of magnetic field generation produced by the superconducting magnet in the cryostat system. From the results, there is a small external magnetic field around the QHR system.