Unlock instant, AI-driven research and patent intelligence for your innovation.

Free layer for CPP GMR enhancement

The use of a Fe25% Co/NiFe composite free layer with controlled thickness in CPP GMR read heads addresses the challenges of high CPP GMR ratios, low coercivity, and low positive magnetostriction, enhancing the stability and performance of CPP GMR read heads by achieving a GMR ratio of at least 5.9% and maintaining desirable magnetostriction.

Inactive Publication Date: 2008-04-24
HEADWAY TECHNOLOGIES INC
View PDF27 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The new structure achieves higher CPP GMR ratios while maintaining low coercivity and desirable magnetostriction, improving the stability and performance of CPP GMR read heads, with confirmed results showing a GMR ratio of at least 5.9% and coercivity between 5 and 10 Oe.

Problems solved by technology

None of the prior art inventions listed above achieve all three of these, particularly the low positive magnetostriction

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0020] It is well known that besides the requirement of a reasonable RA (resistance-area product) and higher CPP GMR, the free layer of the CPP GMR structure has to be magnetically soft and its magnetostriction constant needs to be within the desirable range (positive 1-3×10−6). The present invention describes a new free layer design for a spin valve having enhanced CPP GMR.

[0021] While it is known that Fe rich CoFe can be used in CPP GMR spin valve structures for CPP GMR ratio improvement, this is offset by the fact that Fe rich CoFe also has too large an Hc (coercivity) value, as well as undesirable magnetostriction, to be useful as a free layer. To overcome this difficulty we have made use of the fact that the magnetic properties of a composite free layer made of CoFe and NiFe can be adjusted through control of the thickness ratio between the NiFe and the CoFe.

[0022] In conventional (standard) CPP spin valve structures, composite free layers made of CoFe(10%) and NiFe(19%) have...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

By using a composite free layer of Fe25% Co / NiFe, an improved CPP GMR device has been created. The resulting structure yields a higher CPP GMR ratio than prior art devices, while maintaining free layer softness and acceptable magnetostriction. A process for manufacturing the device is also described.

Description

[0001] This is a divisional application of U.S. patent application Ser. No. 10 / 845,888, filed on May 14, 2004, which is herein incorporated by reference in its entirety, and assigned to a common assignee.FIELD OF THE INVENTION [0002] The invention relates to the general field of CPP GMR read heads with particular reference to the free layer sub-structure. BACKGROUND OF THE INVENTION [0003] The principle governing the operation of most magnetic read heads is the change of resistivity of certain materials in the presence of a magnetic field (magneto-resistance or MR). Magneto-resistance can be significantly increased by means of a structure known as a spin valve where the resistance increase (known as Giant Magneto-Resistance or GMR) derives from the fact that electrons in a magnetized solid are subject to significantly less scattering by the lattice when their own magnetization vectors (due to spin) are parallel (as opposed to anti-parallel) to the direction of magnetization of their...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): G11B5/39G11B5/127G11B5/33H01F10/14H01F10/16H01F10/32H01L43/08H01L43/10
CPCG11B5/39Y10T428/1129Y10T428/12931
Owner HEADWAY TECHNOLOGIES INC