Magnetic memory device
View Patent ↗According to one embodiment, a magnetic memory device includes a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, wherein the first magnetic layer includes a first sub-magnetic layer in a polycrystalline state and a second sub-magnetic layer in an amorphous state.
1. A magnetic memory device comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction;
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer; and
an under layer on which the first magnetic layer is provided,
wherein:
the first magnetic layer contains at least iron (Fe) and boron (B) and includes a first sub-magnetic layer in a polycrystalline state and a second sub-magnetic layer in an amorphous state,
a composition ratio (atomic %) of boron (B) in the second sub-magnetic layer is greater than a composition ratio (atomic %) of boron (B) in the first sub-magnetic layer, and
the second sub-magnetic layer is in direct contact with the under layer.
2. The device of claim 1 , wherein the first sub-magnetic layer is provided between the nonmagnetic layer and the second sub-magnetic layer.
3. The device of claim 1 , wherein the second sub-magnetic layer is thinner than the first sub-magnetic layer.
4. The device of claim 1 , wherein the under layer contains a nitrogen compound or an oxygen compound.
5. A magnetic memory device comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
wherein:
the first magnetic layer includes a first sub-magnetic layer in a polycrystalline state and a second sub-magnetic layer in a single crystalline state, and the first sub-magnetic layer and the second sub-magnetic layer are provided continuously without any nonmagnetic layer interposed therebetween.
6. The device of claim 5 , wherein the first sub-magnetic layer is provided between the nonmagnetic layer and the second sub-magnetic layer.
7. The device of claim 5 , wherein the second sub-magnetic layer is thinner than the first sub-magnetic layer.
8. The device of claim 5 , wherein the first magnetic layer contains at least iron (Fe) and boron (B).
9. A magnetic memory device comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
wherein:
the first magnetic layer includes a first sub-magnetic layer in a polycrystalline state and a second sub-magnetic layer in a polycrystalline state,
an average grain size of polycrystals included in the second sub-magnetic layer is less than an average grain size of polycrystals included in the first sub-magnetic layer, and
the first sub-magnetic layer and the second sub-magnetic layer are provided continuously without any nonmagnetic layer interposed therebetween.
10. The device of claim 9 , wherein the first sub-magnetic layer is provided between the nonmagnetic layer and the second sub-magnetic layer.
11. The device of claim 9 , wherein the second sub-magnetic layer is thinner than the first sub-magnetic layer.
12. The device of claim 9 , wherein the first magnetic layer contains at least iron (Fe) and boron (B).
13. A magnetic memory device comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
wherein:
the first magnetic layer includes a first sub-magnetic layer in a crystalline state and a second sub-magnetic layer in a crystalline state, and
the second sub-magnetic layer has lower crystal orientation than the first sub-magnetic layer.
14. The device of claim 13 , wherein the first sub-magnetic layer is provided between the nonmagnetic layer and the second sub-magnetic layer.
15. The device of claim 13 , wherein the second sub-magnetic layer is thinner than the first sub-magnetic layer.
16. The device of claim 13 , wherein the first magnetic layer contains at least iron (Fe) and boron (B).