| The impressive pace of silicon-based digital electronics is regarded by some as coming to its close due to severe material limitations. For this reason new ideas based on new materials have been proposed. The current leading candidate is the field of spintronics, which, integrated with optoelectronics, promises to take information processing technologies to clock speeds not foreseen just some years ago. In spintronics, the spin degree of freedom is coupled to the carrier degrees of freedom to produce new paradigms of the digital device and circuit operation. Semimagnetic semiconductors are the natural material choice for spintronics. Among them, the most studied is Cd1-x MnxTe, which can be produced as single crystals of optimal quality, even for very high Mn substitution.; In this thesis, we study structural properties of Cd1-xMn xTe by x-ray diffractometry and perform extensive ultrafast optical tests. Our aim is to understand the carrier and spin dynamics in these materials and assess Cd1-xMnxTe applicability for spintronics and ultrafast magneto-optics. In our x-ray diffraction studies, we confirmed that our Cd1-xMnxTe crystals are of the highest quality, presenting an almost perfect zinc-blende structure. Our ultrafast measurements consisted of time-resolved magneto-optical sampling, femtosecond pump-probe spectroscopy, and the recently developed time-resolved magnetization modulation spectroscopy. Our results show a large magneto-optical effect and overall ultrafast carrier and spin dynamics in Cd1-x MnxTe which, added to the Cd1-xMnx Te excellent crystalline properties, make this material one of the best candidates for the practical realization of spintronic and magneto-optoelectronic devices. |
