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Tunneling magnetoresistive (TMR) device and tunneling magnetoresistive read head

A technology of tunneling magnetoresistance and devices, which is applied in the manufacture of flux-sensitive magnetic heads, magnetic field-controlled resistors, magnetic recording heads, etc.

Active Publication Date: 2016-11-09
WESTERN DIGITAL TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since magnetic noise is also proportional to the TMR signal, magnetic noise is the dominant noise source in TMR devices if the TMR is large and will limit the achievable signal-to-noise ratio (SNR)

Method used

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  • Tunneling magnetoresistive (TMR) device and tunneling magnetoresistive read head
  • Tunneling magnetoresistive (TMR) device and tunneling magnetoresistive read head
  • Tunneling magnetoresistive (TMR) device and tunneling magnetoresistive read head

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Embodiment Construction

[0015] figure 2 is a highly schematic cross-sectional view showing the structure of a prior art TMR read head 100 as used in a magnetic recording disk drive. This cross-sectional view is a view of what is commonly referred to as the air bearing surface (ABS) of the TMR readhead 100 . The TMR read head 100 includes a sensor stack formed between two ferromagnetic shield layers S1, S2, typically made of electroplated NiFe alloy films. The lower shield S1 is typically smoothed by chemical mechanical polishing (CMP) to provide a smooth surface for growing the sensor stack. The sensor stack includes: a ferromagnetic reference layer 120 with a pinned magnetization 121 oriented laterally (away from the page); an in-plane rotating magnetization 111; and an electrically insulating tunneling barrier layer 130, typically magnesium oxide (MgO), between the ferromagnetic reference layer 120 and the ferromagnetic free layer 110. In the quiescent state, ie, no magnetic field applied from ...

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Abstract

The invention dsicloses a tunneling magnetoresistive (TMR) device and a tunneling magnetoresistive read head. According to the invention, a tunneling magnetoresistance (TMR) or magnetic tunnel junction MTJ device comprises a thin MgO tunneling barrier layer and a free ferromagnetic multilayer which includes a CoFeB first ferromagnetic layer, a face centered cubic (fcc) NiFe compensation layer with negative magnetostriction, and a body centered cubic (bcc) NiFe insertion layer between the CoFeB layer and the fcc NiFe compensation layer. An optional ferromagnetic nanolayer (e.g CoFe) may be located between the MgO barrier layer and the CoFeB layer. An optional amorphous separation layer may be located between the CoFeB layer and the bcc NiFe insertion layer. The bcc NiFe insertion layer (including amorphous separation layer) prevents the fcc NiFe compensation layer from adversely affecting the crystalline formation of the MgO and CoFeB layers during annealing. The bcc NiFe insertion layer also increases the TMR and lowers the Gilbert damping constant of the free ferromagnetic multilayer.

Description

technical field [0001] The present invention relates generally to tunneling magnetoresistive (TMR) devices, and more particularly, to a TMR read head having a magnesium oxide (MgO) tunneling barrier layer. Background technique [0002] Tunneling magnetoresistive (TMR) devices, also known as magnetic tunnel junction (MTJ) devices, consist of two ferromagnetic layers separated by a thin insulating tunneling barrier layer. The barrier layer is usually made of a metal oxide that is thin enough that quantum mechanical tunneling of charge carriers occurs between the two ferromagnetic layers. Although various metal oxides such as aluminum oxide (Al 2 o 3 ) and titanium oxide (TiO 2 ) as the tunneling barrier material, but the most promising material is crystalline magnesium oxide (MgO). The quantum mechanical tunneling process is electron spin dependent, which means that the resistance measured when a sensing current is applied across the junction depends on the spin-dependent ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B5/39H10N50/10
CPCG11B5/3935G11B5/398G11B5/3987H10N50/85G01R33/098G11B5/3909H01F10/3254H01F10/3295H01F10/3259H01F10/3272G11C11/161H10N50/10B82Y25/00H01F10/32G11B5/33
Inventor Z.高S.吴
Owner WESTERN DIGITAL TECH INC