Spin torque MRAM using bidirectional magnonic writing

摘要

An apparatus is provided for bidirectional writing. A stack includes a reference layer on a tunnel barrier, the tunnel barrier on a free layer, and the free layer on a metal spacer. The apparatus includes an insulating magnet. A Peltier material is thermally coupled to the insulating magnet and the stack. When the Peltier/insulating magnet interface is cooled, the insulating magnet is configured to transfer a spin torque to rotate a magnetization of the free layer in a first direction. When the Peltier/insulating magnet interface is heated, the insulating magnet is configured to transfer the spin torque to rotate the magnetization of the free layer in a second direction.

主权项

1. A magnetoresistive random access memory (MRAM) device, comprising:
a magnetic stack, comprising a reference layer adjacent to a tunnel barrier, the tunnel barrier adjacent to a free layer, and the free layer adjacent to a metal spacer; an insulating magnet; a n-type Peltier material thermally coupled to the insulating magnet and the magnetic stack; and a p-type Peltier material thermally coupled to the insulating magnet and the magnetic stack; a first metal lead, a second metal lead, a third metal lead, and a fourth metal lead; wherein the n-type Peltier material is adjacent to the first metal lead and a part of the second metal lead is adjacent to the n-type Peltier material, the p-type Peltier material is adjacent to the fourth metal lead and a different part of the second metal lead is adjacent to the p-type Peltier material; wherein the second metal lead is formed on top of both the n-type Peltier material and the p-type Peltier material; wherein the second metal lead is a different material than both the n-type Peltier material and the p-type Peltier material; wherein the insulating magnet is adjacent to the second metal lead, the stack is adjacent to the insulating magnet, and the third metal lead is adjacent to the stack; wherein a left part of the insulating magnet and the n-type Peltier material together sandwich the part of the second metal lead that is adjacent to the n-type Peltier material; wherein a right part of the insulating magnet and the p-type Peltier material together sandwich the different part of the second metal lead; wherein positive current flows into the first metal lead and out through the fourth metal lead via the n-type Peltier material, the second metal lead, and the p-type Peltier material to cool an interface between the n-type Peltier material and the second metal lead and to cool an interface between the p-type Peltier material and the second metal lead; wherein positive current flows into the fourth metal lead and out through the first metal lead via the p-type Peltier material, the second metal lead, and the n-type Peltier material to heat an interface between the n-type Peltier material and the second metal lead and to heat an interface between the p-type Peltier material and the second metal lead; wherein cooling of the interface between the n-type Peltier material and the second metal lead and cooling of the interface between the p-type Peltier material and the second metal lead cause the insulating magnet to transfer a spin torque to rotate a magnetization of the free layer in a first direction, based on positive current flowing into the first metal lead and out through the fourth metal lead; and wherein heating of the interface between the n-type Peltier material and the second metal lead and heating of the interface between the p-type Peltier material and the second metal lead cause the insulating magnet to transfer the spin torque to rotate the magnetization of the free layer in a second direction, based on positive current flowing into the fourth metal lead and out through the first metal lead.