Based Of Mnge Magnetic Semiconductor

In modern information technology, data processing is based on the control of the charge of the carriers, as well as the information storage technique uses spins of the carriers. The use of carrier spin and charge appears promising for a new class of devices such as chips that integrate memory and microprocessor functions, magnetic devices exhibiting gain and ultra-low power transistors. The control of spin-dependent phenomena in conventional semiconductors may lead to many novel properties, such as colossal magneto-resistance, magneto-optical effect, etc. So there is interest in developing magnetic semiconductors which will exhibit ferromagnetism. Nowadays, the. main method of studying ferromagnetic semiconductors is to dope transition elements into semiconductors. There are two originations to realize spin polarization of carriers. The first is the double exchange interaction between transition ions which mediated by oxide. The second is the strong interaction between the d electrons of transition ions and sp electrons of the mother semiconductors, which leads to the splitting of semiconductors' conducting band Thus, spin majority and spin minority are formed, and carriers are spin polarized.Recently, stimulated by the success in (Ga, Mn)As magnetic semiconductors, Ge-based magnetic semiconductors have been investigated by a few groups since they are predicted to realize ferromagnetic semiconductors with a high T_c above 400 K, especially for that group IV elements have the potential compatibility with current Si-based technology. To date, the reported experimental results of Mn doped Ge magnetic semiconductors by these groups are different The (near or above) room temperature ferromagnetism of Mn doped Ge magnetic semiconductors has been found by some groups, but they were proved to be originated by MnGe ferromagnetic compounds subsequently. Park et al. reported the Mn_xGe_1-x magnetic semiconductors with T_c in the range 25 to 116 K. They observed anomalous Hall effect and could control ferromagnetic order through application of a +0.5-volt gate voltage, a value compatible with present microelectronic technology. And Li et al attributed the AHE...