Coherent spin valve and related devices
View Patent ↗Embodiments of the present invention are directed toward the field of spintronics, and in particular, systems and devices capable of performing spin coherent quantum logic operations. The inventive spin valve comprises two ferromagnetic electrode layers, and a non-magnetic conducting layer positioned therebetween. An external magnetic field B 0 is applied in the Z direction, such that the two electrode layers are each magnetized in a direction substantially parallel to the external magnetic field. Rather than attempting to change the magnetization of one of the ferromagnetic layers, as is the case in prior art technologies, it is the direction of the electron spin that is manipulated in the present embodiments while the electron is traveling through the middle, nonmagnetic layer. One of the ferromagnetic electrodes may be the tip of a scanning tunneling microscope (STM). This configuration may further comprise a bias voltage source connected between the STM tip and the other ferromagnetic electrode, such that a spin polarized tunneling current is conducted between the two.
1. A method of performing spintronics, the method comprising:
providing a nonmagnetic, electrically conducting layer positioned adjacent to a first ferromagnetic electrode and a second ferromagnetic electrode;
providing a static magnetic field B 0 to magnetize the first and second ferromagnetic electrodes, each direction of magnetization being substantially parallel to the static magnetic field B 0 ;
providing an RF/microwave signal to the nonmagnetic, electrically conducting layer, the RF/microwave signal having a magnetic field B 1 which is substantially perpendicular to the static magnetic field B 0 ;
interacting the magnetic fields B 1 and B 0 with conducting electrons in the nonmagnetic layer to excite a precessing electron state having a spin resonance frequency, thus generating a spin polarized conducting current; and
detecting a change in the spin polarized conducting current.
2. The method of claim 1 , wherein the method is a spin coherent quantum logic operation.
3. The method of claim 1 , further including a spin echo technique.
4. The method of claim 1 , further including 2D Fourier transform electron spin resonance.
5. The method of claim 1 , wherein the RF/microwave signal comprises a pulse signal of π/2-t 1 -π-t 2 -π/2.
6. The method of claim 1 , wherein the RF/microwave signal comprises a pulse signal of π/2-t 1 -π/2-t-π/2-t 2 -π/2.
7. The method of claim 1 , wherein the RF/microwave signal gates the spin polarized conducting current through the nonmagnetic, electrically conducting layer.