Methods and apparatus of high moment free layers for magnetic tunnel junctions
AssigneeWestern Digital Technologies, Inc.
InventorsJames Mac Freitag, Zheng Gao
Life of this patent
Estimating the term…
Abstract
The present disclosure generally relates to magnetoresistive device apparatus and methods. The magnetoresistive device includes a read head. The read head is a tunneling magnetoresistive reader that includes a multilayer free layer structure. The multilayer structure includes one or more layers of Co or FCC FeCo sandwiched between a BCC CoFe50 nanolayer and an amorphous CoFeB layer. The one or more layers of Co or FCC FeCo create nanocrystalline disorder that allows the thickness of the amorphous CoFeB layer to be reduced while retaining or even improving TMR and reducing the interlayer coupling field.
Claims29
A magnetic sensor, comprising:
- a barrier layer;
- a free layer above the barrier layer, the free layer comprising:
- a ferromagnetic nanolayer on the barrier layer,
- a boron layer above the ferromagnetic nanolayer, the boron layer comprising one or more of CoFeB or CoB, and
- one or more layers between the ferromagnetic nanolayer and the boron layer, the one or more layers comprising one or more of Co or CoFe, wherein the one or more layers between the ferromagnetic nanolayer and the boron layer comprise:
- a first layer comprising CoFe;
- and
- a second layer comprising Co;
- and
- a non-ferromagnetic capping layer above the free layer.
A magnetic sensor, comprising:
- a seed layer;
- a barrier layer above the seed layer;
- a free layer above the barrier layer, the free layer comprising:
- a ferromagnetic nanolayer on the barrier layer, the ferromagnetic nanolayer comprising a crystalline structure that is BCC;
- an amorphous layer above the ferromagnetic nanolayer,
- one or more layers between the ferromagnetic nanolayer and the amorphous layer, the one or more layers comprising a crystalline structure that is FCC, wherein the one or more layers between the ferromagnetic nanolayer and the amorphous layer comprise:
- a first layer comprising CoFe;
- and
- a second layer comprising Co;
- and
- a non-ferromagnetic capping layer above the free layer.
A magnetic sensor, comprising:
- a seed layer;
- a barrier layer above the seed layer;
- a free layer above the barrier layer, the free layer comprising:
- a ferromagnetic nanolayer on the barrier layer;
- a boron layer above the ferromagnetic nanolayer, the boron layer comprising one or more of CoFeB or CoB, and the boron layer comprising a thickness of 15 Angstroms or less,
- one or more layers between the ferromagnetic nanolayer and the boron layer, the one or more layers each comprising a thickness of 10 Angstroms or less, wherein the one or more layers between the ferromagnetic nanolayer and the boron layer comprise:
- a first layer comprising CoFe;
- and
- a second layer comprising Co;
- and
- a non-ferromagnetic capping layer above the free layer.
Dependencies are inferred from the claim text.