Abstract
Diluted ferromagnetic semiconductors (FMS) are in the focus of intense research due to their potential applications in spintronics and their striking new physical properties. So far Mn-doped III-V compound semiconductors such as GaMnAs are the most important and best understood ones, but they are ferromagnetic only at well below room temperature. An interesting alternative could be magnetic semiconductors based on elemental semiconductors, also owing to their compatibility with Si microelectronics. In the last decades, considerable amount of work has been devoted to fabricate Mn-doped Ge and Si FMS. In this article, the structural, magnetic and magneto-transport properties of Mn-doped Ge and Si will be reviewed.
Highlights
A diluted ferromagnetic semiconductor should exhibit strong magneto-transport effects, namely negative magnetoresistance (MR) and anomalous Hall effect (AHE) [45,46,47], and provide the possibility to control the spin by an external electric field
Measurements alone could be caused by ferromagnetic precipitates, e.g., Mn5 Ge3, in addition to or instead of a ferromagnetic semiconductors (FMS). Hysteresis appears in both the Hall and longitudinal resistance curves, with the same coercive field as in the magnetization. Such a correlation between AHE, MR, and magnetization is usually considered as the signature of FMS, [46,47] where the same set of holes contribute to ferromagnetism and transport [10]
They concluded that the doped Mn ions substitute for Si sites based on a detailed analysis of the extended X-ray absorption fine structure (XAFS) together with the X-ray absorption near-edge structure spectra at the MnK -edge
Summary
Charge and spin are used separately. Charge, on one hand, is used for the computing. Transistors operate by controlling the flow of charge carriers through the semiconductor by applied electric fields. Datta and Das [3] extended the principle of spintronics to semiconductors They proposed a spin-FET (field effect transistor), where the source and the drain are ferromagnets acting as the injector and detector of the electron spin. Even for samples with large Mn concentrations, more and more evidences indicate the impurity-band formation [11] It is currently unclear whether the hole states close to the. The discovery of the GaMnAs FMS opened new routes to the successful combination of magnetism and semiconductor physics. The hole mobility in GaMnAs might be physically limited by the large effective mass of holes localized inside an impurity band [16]
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