The use of supermalloy-like materials such as NiFeMe where Me is one or more of Mo, Cr, and Cu for the side and top shields of a magnetic bit sensor is shown to provide better shielding protection from stray fields because of their extremely high permeability. Moreover, the side shield may comprise a stack in which a Ni, Fe, Co, FeNi, CoFe, or FeCo is sandwiched between two NiFeMe layers to enhance the bias field on an adjacent free layer. Including NiFeMe in a side shield results in an increase in readback amplitude under the same asymmetric sigma. For these sensors, the signal to noise ratio was higher and the bit error rate was lower than with conventional materials in the side shield. A method is disclosed for forming a magnetic bit sensor having supermalloy-like materials in the side shields.

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.

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 read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S2). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S1). In a three terminal configuration, a first current flows between S1 and S2 such that the AP1 reference layer produces a first spin torque on the FL, and a second current flows across the SHE layer thereby generating a second spin torque on the FL that opposes the first spin torque. When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S1, or vice versa.

Provided is a magnetoresistance effect device comprising a magnetoresistance effect element including a first ferromagnetic layer, a second ferromagnetic layer and a spacer layer, and a high-frequency signal line. The high-frequency signal line includes an overlapping part disposed at a position overlapping the magnetoresistance effect element and a non-overlapping part disposed at a position not overlapping the magnetoresistance effect element in a plan view from a stacking direction. At least a part of the non-overlapping part is disposed below the overlapping part in the stacking direction, assuming that the overlapping part is above the magnetoresistance effect element in the stacking direction.

A junction shield (JS) structure and method of forming the same are 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 at a stripe height (SH) from the ABS. The JS structure has a lower layer (JS1) with 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 decreasing amplitude for a reader with low AR. The JS1 layer may be antiferromagnetically coupled to an upper JS layer for stabilization.

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 single layer (JS1) adjacent to each sensor sidewall and 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.

A read head is disclosed wherein a Spin Hall Effect (SHE) layer is formed on a free layer (FL) in a sensor and between the FL and top shield (S2). Preferably, the sensor has a seed layer, an AP2 reference layer, antiferromagnetic coupling layer, AP1 reference layer, and a tunnel barrier sequentially formed on a bottom shield (S1). When the stripe heights of the FL and SHE layer are equal, a two terminal configuration is employed where a current flows between one side of the SHE layer to a center portion thereof and then to S1, or vice versa. As a result, a second spin torque is generated by the SHE layer on the FL that opposes a first spin torque from the AP1 reference layer on the FL.

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.

A reader includes a free layer and a side shield that biases the free layer. The side shield includes a main bias layer having a first magnetic moment value and a first magnetization direction. The side shield also includes a compensation bias layer having a second magnetic moment value that is less than the first magnetic moment value and a second magnetization direction that is opposite to the first magnetization direction.