Magnetic and transport properties of the ferromagnetic semiconductor heterostructures (In,Mn)As/(Ga,Al)Sb

We have investigated the magnetic and transport properties of (In,Mn)As thin films grown on a (Ga,Al)Sb layer. Strong perpendicular magnetic anisotropy is observed for the (In,Mn)As layer, the thickness of which is less than the critical value required for relaxation of lattice-mismatch-induced strain. The anomalous Hall coefficient is found to be approximately proportional to the square of resistivity in the low-field region. Large negative magnetoresistance is found to occur over a magnetic field range significantly wider than that for the ferromagnetic hysteresis loop.