We have studied magnetic and transport properties of a series of Gai1-xMnxAs/GaAs samples with different Mn concentrations (x = 0.015-0.071), For Mn content higher than about 0.02, carrier(hole)-induced ferromagnetism is observed. Samples with x = 0.035 and 0.043 behave as ferromagnetic dirty metals. With further increase of Mn content above x ∼ 0.05, the zero-field resistivity turns a semiconducting temperature dependence. Very large negative magnetoresistance is observed in nonmetallic samples near the metal-nonmetal transitions both in the low and the high Mn content regimes.
ASJC Scopus subject areas
- 化学 (全般)