Spin-valve transistor

Abstract

A spin-valve transistor has an emitter, a base including a spin-valve film in which two magnetic layers are stacked with interposing a nonmagnetic layer between the two magnetic layers, and a collector, the spin-valve film having a stacked structure of M/A/M′ or M/B/M′ and the spin-valve film being (100)-oriented, where each of M and M′ includes at least one element selected from the group consisting of Fe, Co, Ni and an alloy including Fe, Co, Ni, A includes at least one element selected from the group consisting of Au, Ag, Pt, Cu and Al, and B includes at least one element selected from the group consisting of Cr and Mn.

What is claimed is:  
     
         1 . A spin-valve transistor, comprising: 
 an emitter;    a base comprising a spin-valve film in which two magnetic layers are stacked with interposing a nonmagnetic layer between the two magnetic layers; and    a collector;    the spin-valve film having a stacked structure of M/A/M′ or M/B/M′ and the spin-valve film being (100)-oriented,    where each of M and M′ comprises at least one element selected from the group consisting of Fe, Co, Ni and an alloy including Fe, Co, Ni; A comprises at least one element selected from the group consisting of Au, Ag, Pt, Cu and Al; and B comprises at least one element selected from the group consisting of Cr and Mn.    
     
     
         2 . The spin-valve transistor according to  claim 1 , wherein at least one of the emitter and the collector comprises a III-V semiconductor.  
     
     
         3 . The spin-valve transistor according to  claim 2 , wherein the III-V semiconductor is selected from the group consisting of GaAs, GaN, GaP, InAs and InSb.  
     
     
         4 . The spin-valve transistor according to  claim 1 , wherein the emitter comprises a semiconductor thin film, the collector comprises a semiconductor thin film or a stacked film comprising a semiconductor and a metal, the semiconductor in the collector having smaller forbidden band width than the semiconductor in the emitter.  
     
     
         5 . The spin-valve transistor according to  claim 1 , wherein a thickness of the magnetic layer is sufficiently smaller as compared with an electron mean free path in the magnetic layer.  
     
     
         6 . The spin-valve transistor according to  claim 5 , wherein a thickness of the magnetic layer is about 2 nm or less.  
     
     
         7 . The spin-valve transistor according to  claim 1 , wherein a tunnel junction is formed between the emitter and the base.  
     
     
         8 . The spin-valve transistor according to  claim 1 , wherein a Schottky junction is formed between the emitter and the base.  
     
     
         9 . A spin-valve transistor, comprising: 
 a spin-valve film comprising a first magnetic layer and a second magnetic layer stacked with interposing a nonmagnetic layer between the first and the second magnetic layers, the spin-valve film being (100)-oriented;    a first electrode electrically connected to the first magnetic layer;    a second electrode electrically connected to the second magnetic layer;    wherein each of the first and the second magnetic layers comprises at least one element selected from the group consisting of Fe, Co, Ni and an alloy including Fe, Co, Ni; the nonmagnetic layer comprises at least one element selected from the group consisting of Au, Ag, Pt, Cu, Al, Cr and Mn.    
     
     
         10 . A spin-valve transistor according to  claim 9 , 
 wherein the first electrode is (100)-oriented.    
     
     
         11 . A spin-valve transistor according to  claim 9 , further comprising: 
 a substrate formed on the first electrode, the substrate being (100)-oriented.    
     
     
         12 . A spin-valve transistor according to  claim 11 , 
 wherein the substrate comprises a III-V semiconductor.    
     
     
         13 . A spin-valve transistor according to  claim 9 , further comprising: 
 a second nonmagnetic layer formed between the second magnetic layer and the second electrode.    
     
     
         14 . A spin-valve transistor according to  claim 13 , 
 wherein the second magnetic layer comprises at least one element selected from the group consisting of Au, Ag, Pt, Cu, Al, Cr and Mn.    
     
     
         15 . A spin-valve transistor manufactured by a process comprising: 
 forming a first electrode on a substrate being (100)-oriented by epitaxial growth;    forming a first magnetic layer on the first electrode;    forming a nonmagnetic layer on the first magnetic layer;    forming a second magnetic layer on the nonmagnetic layer;    forming a second electrode on the second magnetic layer,    wherein the first magnetic layer, the nonmagnetic layer and the second magnetic layer are formed with a deposition rate within the range of 0.01 nanometers per second to 0.1 nanometers per seconds.