Proton Irradiation Enhancement of Low-Field Negative Magnetoresistance Sensitivity of AlGaN/GaN-Based Magnetic Sensor at Cryogenic Temperature

The longitudinal and transverse magnetoresistances of AlGaN/GaN heterostructure-based micro-Hall sensors were compared with samples irradiated with protons with an energy of 380 keV and fluence of 1014 (protons/cm²). Increases in the elastic and inelastic scattering were deduced from weak localization behavior in both samples. The AlGaN/GaN micro-Hall sensors showed stable magnetic sensitivity in non and irradiated samples and increased resistivity after proton irradiation yielded an enhanced magnetoresistance sensitivity in nonirradiated sensors from 160 to 417 VA^-1T^-1. The minimum detectable magnetic field of irradiated micro-Hall sensors determined from magneto-voltage measurements at ~4 K was similar to the minimum detectable magnetic field in the nonirradiated sensors.