Magnetic and electrical properties of random and digital alloys of GaSb:Mn

We have investigated the effect of Sb/Ga flux ratio on the magnetic and electronic properties of Mn-incorporated GaSb random and digital alloys grown by low-temperature molecular beam epitaxy. The magnetic and magnetotransport properties of Ga1−xMn x Sb random alloys are strongly dependent on Sb/Ga flux ratio. Clear square-like hysteresis loops were observed for Sb/Ga flux ratios between 4.60 and 5.25. The coercive field and negative magnetoresistance increase with decreasing Sb/Ga flux ratio, while the Curie temperature remains constant at approximately 23 K, with no systematic dependence on the hole density. In contrast, the Curie temperatures for the GaSb:Mn digital alloys with different Mn surface coverages depend significantly on the Sb/Ga flux ratio, and it is also directly correlated with the hole density.