Magnetic memory device
According to one embodiment, a magnetic memory device includes a conductive layer, a first magnetic layer, a second magnetic layer, a first nonmagnetic layer, and a controller. The conductive layer includes first and second portions, and a third portion between the first and second portions. The conductive layer includes a first metal and boron. The first magnetic layer is separated from the third portion in a first direction crossing a second direction. The second magnetic layer is provided between the third portion and the first magnetic layer. The first nonmagnetic layer is provided between the first and second magnetic layers. The controller is electrically connected to the first and second portions. The controller supplies a current to the conductive layer. The first metal includes at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
1. A magnetic memory device, comprising:
a conductive layer including a first portion, a second portion, and a third portion between the first portion and the second portion, the conductive layer including a first metal and boron;
a first magnetic layer separated from the third portion in a first direction crossing a second direction, the second direction being from the first portion toward the second portion;
a second magnetic layer provided between the third portion and the first magnetic layer;
a first nonmagnetic layer provided between the first magnetic layer and the second magnetic layer; and
a controller electrically connected to the first portion and the second portion, the controller being configured to supply a current to the conductive layer,
the first metal including at least one selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
2. The device according to claim 1 , wherein the first metal includes at least one selected from the group consisting of Ce, Pr, and Nd.
3. The device according to claim 1 , wherein the first metal includes La.
4. The device according to claim 1 , wherein the first metal includes at least one selected from the group consisting of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
5. The device according to claim 1 , wherein a concentration of boron in the conductive layer is 80 atm % or more.
6. The device according to claim 1 , wherein at least a portion of the conductive layer has a CsCl crystal structure.
7. The device according to claim 1 , wherein at least a portion of the conductive layer includes hexaboride.
8. The device according to claim 1 , wherein
the conductive layer includes a crystal, and
a (001) plane of the crystal crosses the first direction.
9. The device according to claim 1 , wherein
the controller implements:
a first operation of supplying a first current to the conductive layer from the first portion toward the second portion; and
a second operation of supplying a second current to the conductive layer from the second portion toward the first portion.
10. The device according to claim 9 , wherein
the controller is further electrically connected to the first magnetic layer,
the controller further implements a third operation and a fourth operation,
in the first operation, the controller sets a potential difference between the first portion and the first magnetic layer to a first voltage,
in the second operation, the controller sets the potential difference between the first portion and the first magnetic layer to the first voltage,
in the third operation, the controller sets the potential difference between the first portion and the first magnetic layer to a second voltage and supplies the first current to the conductive layer,
in the fourth operation, the controller sets the potential difference between the first portion and the first magnetic layer to the second voltage and supplies the second current to the conductive layer,
the first voltage is different from the second voltage,
a first electrical resistance between the first magnetic layer and the first portion after the first operation is different from a second electrical resistance between the first magnetic layer and the first portion after the second operation, and
an absolute value of a difference between the first electrical resistance and the second electrical resistance is greater than an absolute value of a difference between a third electrical resistance and a fourth electrical resistance, the third electrical resistance being between the first magnetic layer and the first portion after the third operation, the fourth electrical resistance being between the first magnetic layer and the first portion after the fourth operation.
11. The device according to claim 1 , wherein
the third portion includes a first region and a second region, the second region being provided between the first region and the second magnetic layer and including the first metal and boron, and
the first region does not include boron, or a first concentration of boron in the first region is lower than a second concentration of boron in the second region.
12. The device according to claim 11 , wherein the concentration of boron in the second region is 80 atm % or more.
13. The device according to claim 11 , wherein
the conductive layer further includes a third region and a fourth region,
the second region is between the third region and the fourth region in the second direction, and
the third region and the fourth region do not include boron, or a concentration of boron in the third region and a concentration of boron in the fourth region each are lower than the second concentration.
14. The device according to claim 13 , wherein a thickness of the second region along the first direction is thicker than a thickness of the third region along the first direction and thicker than a thickness of the fourth region along the first direction.
15. The device according to claim 1 , wherein
the second magnetic layer is crystalline, and
a lattice length of the second magnetic layer along the first direction is shorter than a lattice constant of the second magnetic layer along the first direction.
16. The device according to claim 1 , wherein an easy magnetization axis of the second magnetic layer crosses the first direction.
17. The device according to claim 1 , further comprising a first insulating region,
the first insulating region not overlapping the second magnetic layer in the first direction,
the first insulating region including the first metal and at least one selected from the group consisting of oxygen and nitrogen.
18. The device according to claim 1 , further comprising a second insulating region,
a direction from the second magnetic layer toward the second insulating region being aligned with the second direction,
the second insulating region including an element and at least one selected from the group consisting of oxygen and nitrogen, and
the second magnetic layer includes the element.
19. The device according to claim 1 , further comprising a third insulating region,
a direction from the first nonmagnetic layer toward the third insulating region being aligned with the second direction,
the third insulating region including an element and at least one selected from the group consisting of oxygen and nitrogen, and
the first nonmagnetic layer includes the element.
20. The device according to claim 1 , wherein
the third portion includes a first region and a second region, the first region including the first metal, the second region being provided between the first region and the second magnetic layer and including the first metal and boron, and
the first region does not include boron, or a first concentration of boron in the first region is lower than a second concentration of boron in the second region.