The present disclosure generally related to a two dimensional magnetic recording (TDMR) read head having a magnetic tunnel junction (MTJ). Both the upper reader and the lower reader have a dual free layer (DFL) MTJ structure between two shields. A synthetic antiferromagnetic (SAF) soft bias structure bounds the MTJ, and a rear hard bias (RHB) structure is disposed behind the MTJ. The DFL MTJ decreases the distance between the upper and lower reader and hence, improves the area density capacity (ADC). Additionally, the SAF soft bias structures and the rear head bias structure cause the dual free layer MTJ to have a scissor state magnetic moment at the media facing surface (MFS).

The present disclosure generally relates to a read head assembly having a dual free layer (DFL) structure disposed between a first shield and a second shield at a media facing surface. The read head assembly further comprises a rear hard bias (RHB) structure disposed adjacent to the DFL structure recessed from the media facing surface, where an insulation layer separates the RHB structure from the DFL structure. The insulation layer is disposed perpendicularly between the first shield and the second shield. The DFL structure comprises a first free layer and a second free layer having equal stripe heights from the media facing surface to the insulation layer. The RHB structure comprises a seed layer, a bulk layer, and a capping layer. The capping layer and the insulation layer prevent the bulk layer from contacting the second shield.

A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, the tunnel barrier layer is expressed by a chemical formula of AB.sub.2O.sub.x, and has a spinel structure in which cations are arranged in a disordered manner, A represents a divalent cation that is either Mg or Zn, and B represents a trivalent cation that includes a plurality of elements selected from the group consisting of Al, Ga, and In.

A method of forming a MTJ with a tunnel barrier having a high tunneling magnetoresistance ratio, and low resistance x area value is disclosed. The method preserves perpendicular magnetic anisotropy in bottom and top magnetic layers that adjoin bottom and top surfaces of the tunnel barrier. A key feature is a passive oxidation step of a first Mg layer that is deposited on the bottom magnetic layer wherein a maximum oxygen pressure is 10-5 torr. A bottom portion of the first Mg layer remains unoxidized thereby protecting the bottom magnetic layer from substantial oxidation during subsequent oxidation and anneal processes that are employed to complete the fabrication of the tunnel barrier and MTJ. An uppermost Mg layer may be formed as the top layer in the tunnel barrier stack before a top magnetic layer is deposited.

A near-field light generator includes a plasmon generator including a plasmon exciting portion on which a surface plasmon is excited, and a near-field transducer including a front end face that generates near-field light from the surface plasmon. The near-field transducer is formed of a first metal material. The plasmon generator includes a first portion formed of the first metal material and a second portion formed of a second metal material. The first portion is in contact with the near-field transducer. The second portion includes at least part of the plasmon exciting portion.

A stacked structure is positioned on a nonmagnetic metal layer. The stacked structure includes a ferromagnetic layer and an intermediate layer interposed between the nonmagnetic metal layer and the ferromagnetic layer. The intermediate layer includes a NiAlX alloy layer represented by Formula (1): Ni.sub.γ1Al.sub.γ2X.sub.γ3 . . . (1), [X indicates one or more elements selected from the group consisting of Si, Sc, Ti, Cr, Mn, Fe, Co, Cu, Zr, Nb, and Ta, and satisfies an expression of 0<γ<0.5 in a case of γ=γ3/(γ1+γ2+γ3)].

A bottom shield in a read head is modified by including a non-magnetic decoupling layer and second magnetic layer on a conventional first magnetic layer. The second magnetic layer has a magnetization that is not exchange coupled to the first magnetic layer, and a domain structure that is not directly affected by stray fields due to domain wall motion in the first magnetic layer. Accordingly, the modified bottom shield reduces shield related noise on the reader and will provide improved signal to noise (SNR) ratio and better reader stability. The second magnetic layer may be further stabilized with one or both of an antiferromagnetic coupling scheme, and insertion of an antiferromagnetic pinning layer. In dual readers, the modified bottom shield is used in either the bottom or top reader although in the latter, first magnetic layer thickness is reduced to maintain reader-to-reader spacing and acceptable bit error rate (BER).

A method of forming a magnetic element. The method includes cooling a substrate to a cryogenic temperature. The method further includes depositing a magnetic layer with a grain refining dopant on the substrate. The magnetic layer with the grain refining dopant deposited on the substrate cooled to the cryogenic temperature has a magnetic moment that is greater than 2 Tesla and very soft magnetic properties.

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 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.