Spin dependent electron transport in hot electron transistor using magnetic metal

研究了肖特基势垒的SVT、双隧道结的MTT和颗粒膜的磁电阻效应。首先，由于引入氧气时不会污染其他靶，因此制作了TMR室。对于SVT，由于Si/Au Schoonbather是重要部件，因此检查了其再现性。结果，定量地获得了磁电流（MC）和转移比的发射极电压依赖性。研究了基片材料及其结构对热电子输运的影响，制备了具有双结结构的MTT，研究了发射极电压对磁电流的影响。据观察，热电子有助于集电极电流。在双隧道结的MTT中，获得了10^3以上的跨导比，MC随发射极电压的增加而逐渐减小。颗粒膜是由铁磁金属纳米颗粒镶嵌在绝缘基体中形成的。针对颗粒膜的三端结构，制备了Fe-MgO颗粒膜，并研究了其磁电阻效应和磁电阻率随颗粒膜结构的变化。根据Fe的组成，颗粒膜的电阻率范围为5.0 - 40 m Ωcm。随着薄膜电阻率的增加，薄膜的磁电阻率也随之增加。具有不同MgO缓冲层厚度的膜的低场MR回路如图1所示。磁共振环的形状取决于MgO缓冲层的厚度。矫顽场附近的尖峰变小。据认为，Fe颗粒的平均尺寸根据MgO缓冲层厚度而变化。随着MgO缓冲层厚度的增加，MR比略有增加，电阻率也增加。用高场测量系统测得最大磁电阻率为2.3%。

a SVT with schottky barrier, a MTT with double tunnel junctions and a magnetoresistance effect of granular films have been investigated. At first, a TMR chamber was made because other target was not contaminated when oxygen was introduced.For the SVT, a reproducibility of Si/Au schottky bather was examined because of an important part. As a result, anemitter voltage dependence of a magneto-current (MC) and a transfer ratio became obtained quantitatively. The effects of the base materials and its structure have been investigated in a hot electron transport.The MTT with double junctions were prepared in order to investigate the emitter voltage dependence of a magneto-current (MC). It was observed that hot electrons contributed to a collector current. A trans far ratio of over 10^3 was obtained in an MTT with double tunnel junction& The MC decreased gradually with increasing emitter voltage. The emitter voltage at which the MC decreased to half its original value was over 1.5V.The granular films are consisted of ferromagnetic metal nano-granules embedded in insulating matrix, Aim of the three terminal structure using granular films, Fe-MgO granular films were also prepared and investigated their magnetoresistance effects and resistivities depending on the film structure. Depending on the Fe composition, the granular films exhibited resistivities ranged from 5.0 to 40m Ωcm. The MR ratio increased with increasing the resistivity of the films. The low field MR loops for the films with various MgO buffer layer thickness are shown in figure 1. The shape of MR loop was different depending on the MgO buffer layer thickness. The sharp peaks near the coercive field become small. It is thought that the average size of Fe granules has changed according to the MgO buffer layer thickness. The MR ratio slightly increased with increasing the MgO buffer layer thickness and the resistivity also increased. The maximum MR ratio of 2.3% was obtained with the high field measurement system.