Spatially resolved inhomogeneous ferromagnetism in (Ga,Mn)As diluted magnetic semiconductors: A microscopic study by muon spin relaxation

Thin epitaxial films of the diluted magnetic semiconductor (DMS) GaMnAs have been studied by low energy muon spin rotation and relaxation (LE-mu SR) as well as by transport and magnetization measurement techniques. LE-mu SR allows measurements of the distribution of magnetic field on the nanometer scale inaccessible to traditional macroscopic techniques. The spatial inhomogeneity of the magnetic field is resolved: although homogeneous above T-c, below T-c the DMS consists of ferromagnetic and paramagnetic regions of comparable volumes. In the ferromagnetic regions the local field inhomogeneity amounts to 0.03 T.