1. A magnetic tunnel junction, comprising:
a reference element;
a compensation element having an opposite magnetization moment to a magnetization moment of the reference element;
a free magnetic layer between the reference element and the compensation element, the free magnetic layer having a saturation moment value being greater than 1100 emucc;
an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the reference element; and
an electrically insulating layer separating the compensation element from the free magnetic layer.
2. A magnetic tunnel junction according to claim 1, wherein the free magnetic layer comprises Co100-X-YFeXBX wherein X is a value being greater than 30 and Y is a value being greater than 15.
3. A magnetic tunnel junction according to claim 1, wherein the free magnetic layer has a saturation moment value greater than 1500 emucc.
4. A magnetic tunnel junction according to claim 1, wherein the electrically insulating layer has a thickness in a range from 3 to 15 Angstroms.
5. A magnetic tunnel junction according to claim 1, wherein the electrically insulating layer is an electrically insulating and electronically reflective layer.
6. A magnetic tunnel junction according to claim 4, further comprising an electrically conductive and nonferromagnetic spacer layer disposed between the compensation element and the electrically insulating layer.
7. A magnetic tunnel junction according to claim 6, wherein the compensation element is a synthetic antiferromagnetic element comprising a Ru, Pd or Cr spacer layer and the nonferromagnetic spacer layer comprises Ta, Cu, Al, Mg, or Au.
8. A magnetic tunnel junction according to claim 5, wherein the electrically insulating and electronically reflective layer comprises TaO, AlO, MgO, SiO, TiO, NiO, TaN, or AlN and has an area resistance value in a range from 1 to 50 ohm\u03bcm2.
9. A magnetic tunnel junction according to claim 1, wherein the reference element has a spin polarization of more than 0.5.
10. A magnetic tunnel junction according to claim 1, wherein the compensation element has a spin polarization in a range from 0.2 to 0.9.
11. A magnetic tunnel junction, comprising:
a reference element;
a compensation element;
a free magnetic layer between the reference element and the compensation element, the free magnetic layer having a saturation moment value being greater than 1100 emucc;
an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the reference element; and
an electrically insulating and electronically reflective layer having a thickness in a range from 3 to 15 Angstroms and being between the compensation element from the free magnetic layer.
12. A magnetic tunnel junction according to claim 11, wherein the electrically insulating and electronically reflective layer comprises TaO, AlO, MgO, SiO, TiO, NiO, TaN, or AlN and has an area resistance value in a range from 1 to 50 ohm\u03bcm2.
13. A magnetic tunnel junction according to claim 11, further comprising an electrically conductive and nonferromagnetic spacer layer disposed between the compensation element and the electrically insulating and electronically reflective layer.
14. A magnetic tunnel junction according to claim 13, wherein the compensation element is a synthetic antiferromagnetic element comprising a Ru, Pd or Cr spacer layer and the nonferromagnetic spacer layer comprises Ta, Cu, Al, Mg, or Au.
15. A magnetic tunnel junction according to claim 11, wherein the free magnetic layer comprises Co100-X-YFeXBY wherein X is a value being greater than 30 and Y is a value being greater than 15.
16. A magnetic tunnel junction according to claim 11, wherein the free magnetic layer has a saturation moment value greater than 1500 emucc.
17. A magnetic tunnel junction according to claim 11, wherein the reference element has a spin polarization of more than 0.5.
18. A magnetic tunnel junction according to claim 11, wherein the compensation element has a spin polarization in a range from 0.2 to 0.9.
19. Aspin-transfer torque memory cell, comprising:
a reference element;
a compensation element having an opposite magnetization moment to a magnetization moment of the reference element;
a free magnetic layer between the reference element and the compensation element, the free magnetic layer having a saturation moment value being greater than 1100 emucc;
an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the reference element;
an electrically insulating and electronically reflective layer having a thickness in a range from 3 to 15 Angstroms and being between the compensation element from the free magnetic layer; and
an electrically conductive and nonferromagnetic spacer layer disposed between the compensation element and the electrically insulating and electronically reflective layer.
20. A magnetic tunnel junction according to claim 19, wherein the free magnetic element has a saturation moment value greater than 1500 emucc.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An electronic device characterized by comprising:
an external device connecting connector which is connected to a power supplying connector of an external device having a power supplying function and receives power supplied from said external device;
an electronic circuit which performs predetermined operation upon reception of the power supplied from said external device through said external device connecting connector; and
an electromagnet which is provided to said external device connecting connector and electrically connected between said external device connecting connector and said electronic circuit, generates a magnetic force when a power supply current supplied from said external device flows therethrough, and attracts a predetermined portion formed of a magnetic body of said power supplying connector, to maintain a fitting state between said external device connecting connector and said power supplying connector.
2. An electronic device according to claim 1, characterized in that
said electronic circuit comprises a rechargeable battery and a charging circuit to charge said rechargeable battery,
said external device comprises a charging power supply unit having a power supplying function to charge said rechargeable battery, and
when said charging circuit receives power supplied from said charging power supply device through said external device connecting connector to charge said rechargeable battery, during a quick charging period in which a voltage difference between a power supply and said rechargeable battery is not less than a predetermined value, said charging circuit drives said electromagnet with a charging current having a predetermined current value to maintain a constant fitting state between said power supplying connector and said external device connecting connector, during a trickle charging period in which the voltage difference becomes smaller than the predetermined value, said charging circuit drives said electromagnet with a charging current having a current value corresponding to the voltage difference to gradually weaken the fitting state between said power supplying connector and said external device connecting connector, and at charging end when the voltage difference disappears, said charging circuit stops supplying the charging current to cancel the fitting state.
3. An electronic device according to claim 1, characterized in that said electromagnet is provided to accompany said external device connecting connector.
4. An electronic device according to claim 1, characterized in that said electromagnet is arranged in the vicinity of said external device connecting connector.
5. An electronic device according to claim 1, characterized in that said electromagnet is arranged at a position on said external device connecting connector which opposes a predetermined portion formed of a magnetic body of said power supplying connector when said external device connecting connector and said power supplying connector are fitted with each other.
6. An electronic device according to claim 1, characterized in that
said external device connecting connector comprises a magnetic case which fits with said power supplying connector, and
said electromagnet comprises a coil which is wound around said magnetic case and through which a power supply current supplied from said external device flows.
7. An electronic device according to claim 1, characterized in that said external device connecting connector is governed by a USB standard.
8. A connector fitting method characterized by comprising:
the step of fitting a power supplying connector of an external device having a power supplying function to an external device connecting connector of an electronic device which receives power from the external device; and
the step of fitting the two connectors so that an electromagnet which is provided to the external device connecting connector and electrically connected between the external device connecting connector and the electronic circuit generates a magnetic force when a power supply current supplied from the external device flows to an electronic circuit of the external device, and attracts a predetermined portion formed of a magnetic body of the power supplying connector, thus maintaining a fitting state between the external device connecting connector and the power supplying connector.
9. A connector fitting method according to claim 8, characterized in that the step of maintaining comprises
the step of driving the electromagnet with a charging current having a predetermined current value, during a quick charging period in which a voltage difference between a power supply and the rechargeable battery of an electronic circuit is not less than a predetermined value, to maintain a constant fitting state between the power supplying connector and the external device connecting connector, and
the step of driving the electromagnet with a charging current having a current value corresponding to the voltage difference, during a trickle charging period in which the voltage difference becomes smaller than the predetermined value, to gradually weaken the fitting state between the power supplying connector and the external device connecting connector.
10. A connector fitting method according to claim 9, further comprising the step of stopping supplying the charging current to the electromagnet, at charging end when the voltage difference disappears, to cancel the fitting state.