Magnetic device with optimized heat confinement
View Patent ↗The present disclosure concerns a magnetic element to be written using a thermally-assisted switching write operation comprising a magnetic tunnel junction formed from a tunnel barrier being disposed between first and second magnetic layers, said second magnetic layer having a second magnetization which direction can be adjusted during a write operation when the magnetic tunnel junction is heated at a high threshold temperature; an upper current line connected at the upper end of the magnetic tunnel junction; and a strap portion extending laterally and connected to the bottom end of the magnetic tunnel junction; the magnetic device further comprising a bottom thermal insulating layer extending substantially parallel to the strap portion and arranged such that the strap portion is between the magnetic tunnel junction and the bottom thermal insulating layer. The magnetic element allows for reducing heat losses during the write operation and has reduced power consumption.
1. A magnetic element to be written using a thermally-assisted switching write operation, comprising a magnetic tunnel junction formed from a tunnel barrier being disposed between first and second magnetic layers, said second magnetic layer having a second magnetization which direction can be adjusted during the write operation when the magnetic tunnel junction is heated at a high threshold temperature; an upper current line connected at the upper end of the magnetic tunnel junction; and a strap portion extending laterally and connected to the bottom end of the magnetic tunnel junction;
the magnetic device further comprising a bottom thermal insulating layer extending substantially parallel to the strap portion and arranged such that the strap portion is between the magnetic tunnel junction and the bottom thermal insulating layer.
2. The magnetic element according to claim 1 , further comprising an upper thermal insulating layer arranged at the upper end of the magnetic tunnel junction, between the upper current line and the magnetic tunnel junction.
3. The magnetic element according to claim 1 , further comprising a lateral thermal insulating layer, laterally embedding at least a portion of the magnetic tunnel junction.
4. The magnetic element according to claim 3 , said at least a portion of the magnetic tunnel junction comprises the bottom magnetic layer, the upper magnetic layer, the tunnel barrier, or a combination of any of them.
5. The magnetic element according to claim 3 , said at least a portion of the magnetic tunnel junction comprises the whole magnetic tunnel junction.
6. The magnetic element according to claim 1 , wherein the thermal insulating layer has a thermal conductivity lower than 1.0 Wm −1 ° C. −1 .
7. The magnetic element according to claim 1 , wherein the thermal insulating layer is made from a low-K material.
8. The magnetic element according to claim 1 , wherein the magnetic tunnel junction further comprises an upper thermal barrier between the upper current line and the magnetic tunnel junction, and a bottom thermal barrier between the magnetic tunnel junction and the strap portion.
9. The magnetic element according to claim 8 , wherein the longitudinal thermal barriers have an electrical resistance lower than the electrical resistance of the tunnel barrier by a factor of at least ten.
10. The magnetic element according to claim 1 , further comprising an electrically insulating liner layer embedding the magnetic tunnel junction.
11. The magnetic element according to claim 1 , further comprising a select transistor connected at the lower end of the magnetic tunnel junction via the strap portion and that can be activated to apply a heating current to said magnetic tunnel junction via the upper current line, for heating magnetic tunnel junction at the high threshold temperature.
12. A magnetic memory device comprising a plurality of magnetic elements, each magnetic element being adapted to be written using a thermally-assisted switching write operation and comprising: a magnetic tunnel junction formed from a first magnetic layer, a second magnetic layer having a second magnetization which direction can be adjusted during the write operation when the magnetic tunnel junction is heated at a high threshold temperature, and a tunnel barrier being disposed between a first magnetic layer; a strap portion extending laterally and connected to the bottom end of the magnetic tunnel junction; and a bottom thermal insulating layer extending substantially parallel to the strap portion and arranged such that the strap portion is between the magnetic tunnel junction and the bottom thermal insulating layer.
13. The magnetic memory device according to claim 12 , further comprising one or a plurality of upper current lines, each current line being connected at the upper end of the magnetic tunnel junction.
14. The magnetic memory device according to claim 12 , wherein
each magnetic element further comprises a select transistor connected at the lower end of the magnetic tunnel junction via the strap portion, and wherein the magnetic memory device further comprises one or a plurality of control current lines, each control current line being coupled to the magnetic elements via their select transistor.