Transport in quantum structures of diluted magnetic semiconductors

This paper reviews recent millikelvin studies of magnetoconductance and noise in nanostructures of a diluted magnetic; semiconductor n-Cd1-xMnxTe. These studies were particularly rewarding for probing the influence of magnetic ions upon mesoscopic phenomena. The accumulated results demonstrated the existence of a new driving mechanism: of the universal conductance fluctuations in magnetic systems. Several signatures of spin-glass freezing were observed, such as the appearance of 1/f conductance noise, aging, thermal, and magnetic irreversibilities as well as a strong increase in the amplitude of both conductance fluctuations and noise when temperature and the magnetic field were lowered below the freezing Line. A statistical analysis of conductance noise made it possible to investigate the nature of excitations in spin-glass phase, and to discriminate between competing theoretical models.