Magnetoresistive Sensor Alloyed Layer Noise Reduction
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Solution Overview
Problem
As magnetic read/write heads become smaller to accommodate increasing areal recording densities, they face challenges with magnetic noise and signal amplitude, leading to inadequate data recovery due to their magnetic response to applied fields.
Innovation Solution
Incorporating an alloyed layer in magnetoresistive (MR) sensors with ferromagnetic and refractory materials, such as Co, Fe, Ni, CoFe, or NiFe, and Ta, Nb, Hf, Zr, which are amorphous and magnetic, to increase stability and signal-to-noise ratio by reducing magnetic noise and maintaining magnetic moment strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MR sensor size is reduced to accommodate higher areal recording densities, then storage capacity is improved, but magnetic noise increases and signal amplitude decreases
Solution Approach 1:
The patent applies composite materials by combining ferromagnetic materials (such as CoFe, NiFe) with refractory materials (such as Ta, Nb, Hf, Zr) to form alloyed layers within the MR sensor structure. These composite alloyed layers provide both magnetic properties for signal detection and structural stability to reduce magnetic noise, thereby maintaining high signal-to-noise ratio even in miniaturized sensors designed for higher areal recording densities
2Length of moving object
If MR sensor size is reduced, then device miniaturization is improved, but magnetic moment strength decreases
Solution Approach 1:
The alloyed layers comprising ferromagnetic and refractory materials provide enhanced magnetic moment strength despite reduced sensor size. The ferromagnetic components contribute strong magnetic moments while the refractory components provide structural stability, allowing the sensor to maintain adequate magnetic response in a miniaturized configuration
Solution Approach 2:
The patent utilizes parameter changes by carefully controlling the thickness and composition of the alloyed layers to optimize magnetic moment strength. By adjusting the ratio of ferromagnetic to refractory materials and the overall layer thickness, the sensor maintains sufficient magnetic response while achieving the desired miniaturization for higher areal recording densities
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the sensitivity and stability of MR sensors, improving signal recovery and reducing magnetic noise, thereby supporting higher areal densities and accurate data retrieval.
Implementation Method 1
an alloyed layer in a magnetoresistive (MR) sensor, the alloyed layer including ferromagnetic material and a refractory material
Implementation Method 2
magnetic flux from the surface of the disc causes rotation of a magnetization vector of a sensing layer of the MR sensor, which in turn causes a change in electrical resistivity of the MR sensor
Data Source
AI summary
Implementations disclosed herein allow a signal detected by a magnetoresistive (MR) sensor to be improved by providing for one or more alloyed layers that each includes a ferromagnetic material and a refractory material. The alloyed layers are provided adjacent to a shield element or between soft magnetic layers of the sensor stack.