An MTJ or MR read sensor is formed by depositing a stack in a reverse order with a free layer (FL) deposited on a lower shield, followed by a tunneling barrier layer (for an MTJ) or a conducting spacer layer (for an MR) and, finally, an antiferromagnetically coupled pinning structure and an upper shield. This reverse order permits a series of etching processes to be accurately performed on the lower shield and the stack together with the formation of biasing layers that are coupled to the lower shield and the stack, without adversely affecting the stability of the pinning structure. Further, the distance between the FL and the shield is accurately determined and repeatable even down to the sub-nm regime. An upper shield can then be formed and also coupled to the biasing layers.

Reader-to-reader separation (RRS) is substantially decreased, and cross-track alignment of top and bottom sensors is improved with a process where a sidewall on the two sensors is formed during a single photolithography and ion beam etch sequence. RRS is minimized since the two sensors share a common reference layer (RL), and shields between the readers are omitted. A RL front portion is formed on a first stack of layers with a first free layer and uppermost first tunnel barrier, and a RL back portion is on a second stack comprising a reference layer and antiferromagnetic coupling layer sequentially formed on an antiferromagnetic layer. The RL may be a single layer or a synthetic antiferromagnetic structure so that the sensors operate in a common mode or differential mode, respectively. A third stack with a bottom second tunnel barrier and overlying second free layer is formed on the RL front portion.

A junction shield (JS) structure is disclosed for providing longitudinal bias to a free layer (FL) having a width (FLW) and magnetization in a cross-track direction between sidewalls in a sensor. The sensor is formed between bottom and top shields and has sidewalls extending from a front side at an air bearing surface (ABS) to a backside that is a stripe height (SH) from the ABS. The JS structure has a lower layer (JS1) with a magnetization parallel to that of the FL, and a tapered top surface such that JS1 has decreasing thickness with increasing height from the ABS. As aspect ratio or AR (SH/FLW) increases above 1, longitudinal bias increases proportionally to slow an increase in asymmetry as AR increases, and without introducing a loss in amplitude for a reader with low AR. The JS1 layer may be antiferromagnetically coupled to an upper JS layer for stabilization.

A reader having a sensor stack and a top shield above the sensor stack. The top shield has an upper surface and a lower surface. The reader also includes at least one side shield below the top shield and adjacent to the sensor stack. The reader further includes a decoupling layer between the upper surface of the top shield and the at least one side shield. The decoupling layer is configured to decouple a first portion of the at least one side shield, proximate to the sensor stack, from at least a portion of the top shield.

An apparatus, according to one embodiment, includes: a plurality of tunnel valve read transducers arranged in an array extending along a read module. Each of the tunnel valve read transducers includes: a sensor structure having a cap layer, a free layer, a tunnel barrier layer, a reference layer and an antiferromagnetic layer, and electrically insulating layers on opposite sides of the sensor structure. Moreover, a height of the free layer measured in a direction perpendicular to a media bearing surface of the read module is less than a width of the free layer measured in a cross-track direction perpendicular to an intended direction of media travel.

A reader of a magnetic recording head includes a sensor stack, a first side shield and a second side shield disposed on opposite sides of the sensor stack in a cross-track dimension, and a bridge. The bridge is configured to align magnetic moments of the first side shield and the second side shield. The bridge is disposed above the sensor stack relative to a media-facing surface of the magnetic recording head and proximate to the first side shield and the second side shield.

A reader having a sensor stack and a top shield above the sensor stack. The top shield has an upper surface and a lower surface. The reader also includes at least one side shield below the top shield and adjacent to the sensor stack. The reader further includes a decoupling layer between the upper surface of the top shield and the at least one side shield. The decoupling layer is configured to decouple a first portion of the at least one side shield, proximate to the sensor stack, from at least a portion of the top shield.

A recording head that includes a reader having a front end at a bearing surface of the recording head and a rear end behind the bearing surface. The reader has a non-rectangular shape with a front-end width that is less than an average width of the reader. A first bias element is positioned proximate to a first side of the reader, and a second bias element is positioned proximate to a second side of the reader. Each of the first and second bias elements has a bias level that is a function of a ratio of the front-end width to the average width of the reader.

A reader having a sensor stack and a top shield above the sensor stack. The top shield has an upper surface and a lower surface. The reader also includes at least one side shield below the top shield and adjacent to the sensor stack. The reader further includes a decoupling layer between the upper surface of the top shield and the at least one side shield. The decoupling layer is configured to decouple a first portion of the at least one side shield, proximate to the sensor stack, from at least a portion of the top shield.

The present disclosure generally relates to a dual free layer (DFL) read head and methods of forming thereof. In one embodiment, a method of forming a DFL read head comprises depositing a DFL sensor, defining a stripe height of the DFL sensor, depositing a rear bias (RB) adjacent to the DFL sensor, defining a track width of the DFL sensor and the RB, and depositing synthetic antiferromagnetic (SAF) soft bias (SB) side shields adjacent to the DFL sensor. In another embodiment, a method of forming a DFL read head comprises depositing a DFL sensor, defining a track width of the DFL sensor, depositing SAF SB side shields adjacent to the DFL sensor, defining a stripe height of the DFL sensor and the SAF SB side shield, depositing a RB adjacent to the DFL sensor and the SAF SB side shield, and defining a track width of the RB.