Method for changing spin relaxation, method for detecting spin current and spintronics device using spin relaxation
The invention relates to a method for changing spin relaxation, a method for detecting a spin current, and a spintronic device using spin relaxation, and spin relaxation is changed through injection of a spin current. A spin current 4 is injected into a material 1 in a certain spin state, so that the spin relaxation time can be controlled.
1. A method for changing spin relaxation comprising:
increasing or decreasing the spin relaxation time by injecting a pure spin current into a material in a spin state,
wherein said the material forms a free layer in a magneto-resistive effect type random access memory comprising the free layer, an insulating layer and a pinned layer.
2. A method for changing spin relaxation comprising:
increasing or decreasing the spin relaxation time by injecting a pure spin current into a material in a spin state,
wherein the material forms a quantum bit that forms a solid-state quantum computer.
3. A method of detecting a pure spin current, comprising:
applying microwaves having a frequency in the vicinity of the ferromagnetic resonance particular to a magnetic material;
changing the pure spin relaxation time by injecting said spin current into said magnetic material where the magnetic moment is in precession; and
detecting change in spin relaxation.
4. The spin current detecting method according to claim 3 , wherein said microwaves are applied when a current in a microwave band flows through a microstrip line extending in the direction parallel to the direction in which said magnetic material is magnetized.
5. A spintronic device using a spin relaxation phenomenon, comprising:
a magneto-resistive effect type random access memory comprising a free layer;
a magnetic field generator for controlling the magnetization direction of the free layer; and
a spin injection electrode contacting the free layer.
6. A spintronic device using a spin relaxation phenomenon, comprising:
a magneto-resistive effect type random access memory comprising a free layer; and
a spin injection electrode contacting the free layer,
wherein the spin injection electrode magnetizes the free layer by pure spin injection.
7. The spintronic device using a spin relaxation phenomenon according to claim 5 , wherein the spin injection electrode for injecting a pure spin current into said free layer is formed of a material in a region of a short mean free path just before metal-insulator transition occurs.
8. The spintronic device using a spin relaxation phenomenon according to claim 5 , wherein the spin injection electrode for injecting a pure spin current into a free layer is formed of an amorphous layer.
9. The spintronic device using a spin relaxation phenomenon according to claim 7 , wherein said spin injection electrode is made of Pt, Au, Pd or an element having an f orbital.
10. A spintronic device using a spin relaxation phenomenon, comprising:
an electro-resistive effect type random access memory comprising a free layer, an insulating layer and a pinned layer; and
a microstrip line extending in the direction parallel to the longitudinal direction of the free layer in the vicinity of the free layer.
11. A spintronic device using a spin relaxation phenomenon, comprising:
a quantum bit forming a solid state quantum computer; and
a spin injection electrode to make contact with the quantum bit.
12. A spintronic device using a spin relaxation phenomenon, comprising:
a spin current detecting portion made of a magnetic material of which the longitudinal direction is perpendicular to the direction in which said spin current transmitting wire extends to make contact with a portion of a spin current transmitting wire for transmitting information as a pure spin current, and
a microstrip line extending in the longitudinal direction of said spin current detecting portion.
13. The spintronic device using a spin relaxation phenomenon according to claim 6 , wherein the spin injection electrode for injecting a pure spin current into said free layer is formed of a material in a region of a short mean free path just before metal-insulator transition occurs.
14. The spintronic device using a spin relaxation phenomenon according to claim 13 , wherein said spin injection electrode is made of Pt, Au, Pd or an element having an f orbital.
15. The spintronic device using a spin relaxation phenomenon according to claim 6 , wherein the spin injection electrode for injecting a pure spin current into a free layer is formed of an amorphous layer.