US 6,989,972 B1Granted

Magnetoresistive sensor with overlapping leads having distributed current

AssigneeWestern Digital (Fremont), LLC

InventorsKroum Stoev, Mathew Gibbons, Francis Liu, Bogdan M. Simion, Aparna C. Vadde, Jing Zhang, Yiming Huai, Marcos M. Lederman

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Abstract

Magnetoresistive (MR) sensors have leads that overlap a MR structure and distribute current to the MR structure so that the current is not concentrated in small portions of the leads. An electrically resistive capping layer can be formed between the leads and the MR structure to distribute the current. The leads can include resistive layers and conductive layers, the resistive layers having a thickness-to-resistivity ratio that is greater than that of each of the conductive layers. The resistive layers may protect the conductive layers during MR structure etching, so that the leads have broad layers of electrically conductive material for connection to MR structures. The broad leads conduct heat better than the read gap material that they replace, further reducing the temperature at the connection between the leads and the MR structure.

Claims15

Dependent claims

A device comprising:

a magnetoresistive structure having a first edge and a second edge that are separated in a track-width direction by a first distance;
a first bias layer adjoining said first edge;
a second bias layer adjoining said second edge;
a first lead layer disposed adjacent to said first bias layer and overlapping said first edge;
and
a second lead layer disposed adjacent to said second bias layer and overlapping said second edge;
wherein said first and second lead layers are separated from each other in said track-width direction by a second distance that is less than said first distance, said first lead layer including a resistive layer and a conductive layer, the resistive layer having a resistivity greater than 10−7 Ωm at 25° C. and a greatest thickness larger than half that of said first lead layer, the conductive layer having a thickness to resistivity ratio that is not more than about that of the resistive layer and a conductive layer resistivity less than 10−7 Ωm.

4 more elements

A device comprising:

a magnetoresistive structure disposed adjacent to a media-facing surface and having a first edge and a second edge that are separated by a first distance in a track-width direction;
a first bias layer adjoining said first edge and a second bias layer adjoining said second edge;
and
a first lead layer disposed adjacent to said first bias layer and extending beyond said first edge to overlap said magnetoresistive structure in a portion of a first region, and a second lead layer disposed adjacent to said second bias layer and extending beyond said second edge to overlap said magnetoresistive structure in a portion of a second region, said first and second regions separated from each other in said track-width direction by a second distance that is less than said first distance, said first and second regions extending further than said magnetoresistive structure from said media-facing surface, said first lead layer including a resistive layer having a resistive layer thickness and a resistive layer resistivity, said first lead layer including a conductive layer having a conductive layer thickness and a conductive layer resistivity, the conductive layer resistivity being less than 10−7 Ωm;
wherein a ratio of said resistive layer thickness to said resistive layer resistivity is greater than or about equal to a ratio of said conductive layer thickness to said conductive layer resistivity.

2 more elements

Dependencies are inferred from the claim text.