Tunneling magnetoresistive element which includes Mg-O barrier layer and in which nonmagnetic metal sublayer is disposed in one of magnetic layers
View Patent ↗In a tunneling magnetoresistive element, an insulating barrier layer is made of Mg—O, and a first pinned magnetic layer has a laminated structure in which a nonmagnetic metal sublayer made of Ta is interposed between a lower ferromagnetic sublayer and an upper ferromagnetic sublayer. The nonmagnetic metal sublayer has an average thickness of about 1 Å or more and about 5 Å or less.
1. A tunneling magnetoresistive element comprising:
a lower magnetic layer;
an insulating barrier layer laminated on the lower magnetic layer; and
an upper magnetic layer laminated on the insulating barrier layer;
wherein one of the lower magnetic layer and the upper magnetic layer is a pinned magnetic layer in which the magnetization direction is pinned and the other is a free magnetic layer in which the magnetization direction is changed in response to an external magnetic field,
the insulating barrier layer is made of magnesium oxide (Mg—O),
the lower magnetic layer has a laminated ferrimagnetic structure in which, from the bottom, a first magnetic layer, a nonmagnetic interlayer, and a second magnetic layer are laminated in that order,
the first magnetic layer has a laminated structure in which at least one nonmagnetic metal sublayer is interposed between ferromagnetic sublayers, the ferromagnetic sublayers are magnetically coupled to each other, and all the ferromagnetic sublayers are magnetized in the same direction and
the nonmagnetic metal sublayer has an average thickness of about 1 Å or more and about 5 Å or less.
2. The tunneling magnetoresistive element according to claim 1 , wherein the nonmagnetic metal sublayer comprises at least one of titanium (Ti), vanadium (V), zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), and tungsten (W).
3. The tunneling magnetoresistive element according to claim 2 , wherein the nonmagnetic metal sublayer comprises tantalum (Ta).
4. The tunneling magnetoresistive element according to claim 1 , wherein the lower magnetic layer is the pinned magnetic layer and the upper magnetic layer is the free magnetic layer.
5. The tunneling magnetoresistive element according to claim 4 , wherein the ferromagnetic sublayers comprise a cobalt-iron (Co—Fe) alloy, the nonmagnetic metal sublayer comprises tantalum (Ta), and the first magnetic layer has a laminated structure comprising Co—Fe/Ta/Co—Fe.