Spin-doping and diamagnetic-paramagnetic interplay in single crystal <i>β</i> -Ga ₂ O ₃

Abstract Beta-phase gallium oxide, being the only ultrawide bandgap semiconductor that can be grown from the melt in form of a high-quality single crystal, holds promise for achieving new functionalities in device fabrication via doping, defect engineering and processing fully compatible with the current silicon technology. We report on magnetic properties of single crystal β -Ga 2 O 3 . While pristine β -Ga 2 O 3 was unambiguously confirmed to be intrinsically diamagnetic, incorporation of Fe into the host matrix was found to give rise to a total net magnetic moment via effective spin doping. The resulting magnetization in Fe-doped β -Ga 2 O 3 crystals was shown by a SQUID magnetometry to exhibit a reversible and reproducible transition between diamagnetic and paramagnetic response to external magnetic field while varying the temperature between 2 K and 350 K. Both undoped and Sn-doped crystals were observed to exhibit a minor paramagnetic contribution to overall predominantly diamagnetic behavior at low temperatures ascribed to Fe impurities detected by SIMS analysis.