| Summary: | 博士 === 國立清華大學 === 材料科學工程學系 === 94 === This work has focused on the study of two new type silicon-base spin transistors. These two new type spin transistors are combined either pseudo spin-valve or magnetic tunneling junction with a p-n junction to form a spin-valve transistor (SVT) or magnetic tunneling transistor (MTT). For SVT, the emitter current (IE) changed from 1uA to 0.968uA at different magnetically states in the common collector (CC) circuitry with an emitter bias (VE) and a base bias (VB) at room temperature (RT). At the same states the base currents (IB) changed form 29.3 uA to 333 nA which gave a magnetocurrent (MC) of 8600% and a transfer ratio (α) of 3E−2. In CC configuration with a base resistor (RB) and an VE of 5.12 V at 77 K gives a large collector current (IC) of more than 95.5 mA and the change is more than 3400% with a α of 2.59E−3. At RT, these changes go down to 98.3 mA and 55.3%, respectively, and the α rises to 5.98E−3. The MC of the collector in a SVT has been studied with both experiments and computer calculations. For MTT, IB change of roughly 6300% has been observed in the CC configuration with an VE and a VB at RT. In CC configuration with VE and RB at RT, the MC of the collector can be stabilized roughly above 40% at VE = 1.25±025V with α of 2.88% in the CC circuitry. IC can be more than 4 uA at the magnetic parallel state. The magnetoimpedance (MZ) effect of the SVT was investigated at RT in the frequency ranged from 100 Hz to 15 MHz. The SVT can be regarded as a complex combination of resistors, inductors, and capacitors; all these components exhibit magnetic hysteresis. It is due to the frequency dependent behavior that R does not reach a minimum at the resonant frequency (fr). The frequency dependences of MZ and MX ratios cross zero at fx = 6.5 MHz and at fr=3.65 MHz, respectively. The shape of magnetoreactance loop is reversed to the magnetoresistance loop. The MZ loop also reverses shape and sign after crossing fx.
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