We have studied the transport and magnetic properties of Ga1-xMnxAs/GaAs with different Mn content (0.015 < x < 0.071) for temperatures 40 mK-250 K and magnetic fields 0-15 T. Ferromagnetic order was observed in the samples with x > 0.02. With incresing Mn concentration, the system undergoes an insulator-metal-insulator transition. Low temperature hopping conduction on the insulator side of the metal-insulator boundaries exhibits giant negative magnetoresistance.
- Diluted magnetic semiconductors
- Giant negative magnetoresistance
- Metal-insulator transition
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering