US 2017/0069341 A1 · BIAS LAYER AND SHIELD BIASING DESIGN

Abstract

A read head is longitudinally biased unidirectionally by laterally abutting soft magnetic layers or multilayers. The soft magnetic layers are themselves magnetically stabilized by layers of antiferromagnetic material that are exchange coupled to them. The same layers of antiferromagnetic materials can be used to stabilize a unidirectional anisotropy of an overhead shield by means of exchange coupling. By including the antiferromagnetic material layer within the patterned biasing structure itself, an additional layer of antiferromagnetic material that normally covers the entire sensor structure is eliminated. The elimination of an entire layer is also advantageous for reducing the inter-sensor spacing in a TDMR (two dimensional magnetic recording) configuration where two sensor are vertically stacked on top of each other.

Claims14

Dependent claims

1-9. (canceled)

A TDMR (two dimensional magnetic recording) read head having longitudinally biased freelayers with unidirectional anisotropy in a longitudinal direction, comprising:

a top sensor top shield;
a patterned top sensor placed beneath and contiguous with said top sensor top shield, wherein said patterned top sensor includes a freelayer having a unidirectional magnetic anisotropy aligned in a horizontal direction;
a top sensor bottom shield;
a non-magnetic spacer layer;
a bottom sensor top shield;
a patterned bottom sensor placed beneath and contiguous with said bottom sensor top shield, wherein said patterned bottom sensor includes a freelayer having a unidirectional magnetic anisotropy aligned in a horizontal direction;
a bottom sensor bottom shield;
wherein
said top and bottom sensors are identical in pattern and structure and symmetrically positioned;
and
an oppositely disposed pair of soft magnetic biasing layers or a multilayer of soft magnetic biasing layers that symmetrically abut patterned lateral sides of each said identically patterned sensor thereby stably biasing each said freelayer therein and producing said unidirectional magnetic anisotropy in each said freelayer therein;
and
a pair of symmetrically formed antiferromagnetic layers exchange coupled to said soft magnetic biasing layers or said multilayer of soft magnetic biasing layers in each said sensor, thereby stabilizing said biasing of each said freelayer therein;
and wherein
said top sensor top shield is also biased in the same direction as said freelayer in said top sensor and wherein said bottom sensor top shield is also biased in the same direction as said freelayer in said bottom sensor and wherein both said top shield of said top sensor and said top shield of said bottom sensor are exchange coupled to said pair of antiferromagnetic layers of their respective sensors and are also provided with a stabilized unidirectional magnetic anisotropy thereby.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application

14/848,376Filed 9 Sep 2015

Published

9 Mar 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

G11B 5/3912
Details related to the use of magnetic thin film layers or to their effects: arrangements in which the active read-out elements are transducing in…
G11B 5/3932
Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding: magnetic biasing films
G11B 5/3951
The sensitive elements being active read-out elements: the active elements being arranged on several parallel planes
G11B 5/3954
The active elements being arranged on several parallel planes: the active elements transducing on a single track

Bias layer and shield biasing design

Life of this patent

Bias layer and shield biasing design

Life of this patent

Abstract

Claims14