Magnetoresistive memory device and manufacturing method of the same
According to one embodiment, a magnetoresistive memory device includes a first magnetic layer, a second magnetic layer on one major surface side of the first magnetic layer via a first nonmagnetic layer, a third magnetic layer on the second magnetic layer via a first Ru layer, a sidewall insulating film on sides of the layers, a fourth magnetic layer on an other major surface side of the first magnetic layer via a second nonmagnetic layer, and a fifth magnetic layer on the fourth magnetic layer via a second Ru layer. The reversed magnetic field of the second magnetic layer is smaller than that of the third and fourth magnetic layers, and the reversed magnetic field of the fifth magnetic layer is smaller than that of the third and fourth magnetic layers.
1. A magnetoresistive memory device comprising:
a first magnetic layer;
a second magnetic layer provided on one major surface side of the first magnetic layer via a first nonmagnetic layer;
a third magnetic layer provided on a surface side the second magnetic layer which is opposite from the first magnetic layer, via a first Ru layer;
a sidewall insulating film provided on sides of the first to third magnetic layers;
a fourth magnetic layer provided on another major surface side of the first magnetic layer via a second nonmagnetic layer, a side surface of the fourth magnetic layer being located on an outer side with respect to a side surface of the first magnetic layer; and
a fifth magnetic layer provided on a surface side of the fourth magnetic layer which is opposite from the first magnetic layer, via a second Ru layer;
wherein:
the second and fourth magnetic layers comprise a material of a same kind, and the third and fifth magnetic layers comprise a material of a same kind,
the second magnetic layer is thinner than the third and fourth magnetic layers, and
the fifth magnetic layer is thinner than the third and fourth magnetic layers.
2. The device of claim 1 , wherein:
the second and fifth magnetic layers have a same magnetization direction, and
the third and fourth magnetic layers have the same magnetization direction, but opposite to the magnetization directions of the second and fifth magnetic layers.
3. The device of claim 1 , wherein:
a reversed magnetic field of the second magnetic layer is smaller than that of the third and fourth magnetic layers, and
a reversed magnetic field of the fifth magnetic layer is smaller than that of the third and fourth magnetic layers.
4. The device of claim 1 , wherein:
the first magnetic layer is a storage layer which stores data,
the first and second nonmagnetic layers are barrier layers into which tunnel current flows,
the second and fourth magnetic layers are reference layers having magnetic anisotropy perpendicular to a film surface, and
the third and fifth magnetic layers are shift cancelling layers having magnetic anisotropy perpendicular to a film surface, which inhibit an influence of a stray magnetic field by the reference layers.
5. The device of claim 1 , wherein each pair of the second and third magnetic layers and the fourth and fifth magnetic layers have an anti-ferromagnetic (synthetic anti-ferromagnetic [SAF]) structure in which the two magnetic layers are anti-ferromagnetically exchange-coupled.
6. The device of claim 1 , wherein:
the third magnetic layer is thicker than the fourth magnetic layer, and
the second magnetic layer is thinner than the fifth magnetic layer.
7. The device of claim 1 , wherein:
a reversed magnetic field of the third magnetic layer is stronger than that of the fourth magnetic layer, and
a reversed magnetic field of the second magnetic layer is weaker than that of the fifth magnetic layer.
8. The device of claim 1 , wherein magnetization directions of the second to fifth magnetic layers are perpendicular to a surface of each of the layers.