Patterned MR device with controlled shape anisotropy
AssigneeHeadway Technologies, Inc.
InventorsYuchen Zhou, Yimin Guo
Life of this patent
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Abstract
A magnetic sensor with increased sensitivity, lower noise, and improved frequency response is described. The sensor's free layer is ribbon shaped and is closely flanked at each long edge by a ribbon of magnetically soft, high permeability material. The side stripes of soft magnetic material absorb external field flux and concentrate the flux to flow into the sensor's edges to promote larger MR sensor magnetization rotation. Side stripes may be located in the plane of the free layer a maximum distance of 0.1 microns, above a plane that includes a top surface of the free layer, or below a plane that includes the bottom surface of the magnetic sensor. Edges of each side stripe may be aligned above or below a portion of the magnetic sensor.
Claims10
A magnetic sensor, comprising:
- a magnetoresistive (MR) device comprising a plurality of layers and patterned in the form of a MR stripe having a first bottom surface, a top layer that is a magnetically free layer having a first top surface, a first thickness, an aspect ratio of at least 5, and a pair of opposing first edges that are equidistant from a center plane that bisects the MR stripe in a lengthwise direction that is perpendicular to a width of the free layer along a second direction, each of the opposing first edges is formed along a side of each of the plurality of layers including the free layer;
- and
- a pair of flux absorbing stripes each with a second bottom surface formed at or above a first plane that includes the first top surface or each with a second top surface formed at or below a second plane that includes the first bottom surface, and having a second edge facing the center plane, and a second thickness between the second top surface and the second bottom surface, a product of flux absorbing stripe magnetization times the second thickness is greater than a product of free layer magnetization times the first thickness, and wherein the second edge of a first flux absorbing stripe is offset from one of the opposing first edges of the free layer and MR sensor along the second direction, and the second edge of a second flux absorbing stripe is offset from another of the opposing first edges of the free layer and MR sensor along the second direction, and wherein adjacent pairs of opposing first edges and second edges are aligned parallel to each other.
Dependencies are inferred from the claim text.