Partial Magnetic Biasing Magnetoresistive Sensor Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetoresistive sensors face challenges in achieving high areal density and signal-to-noise ratio due to increased reader resistance and noise as dimensions decrease, making it difficult to maintain acceptable signal quality at high recording densities.
Innovation Solution
A biasing magnet with a height less than the magnetoresistive stack is positioned adjacent to the stack, optimizing the signal-to-noise ratio by reducing magnetic noise and resistance through partial biasing and strategic placement of permanent magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetoresistive sensor dimensions are decreased to achieve high areal density, then the recording capacity increases, but the reader resistance increases and signal-to-noise ratio deteriorates
Solution Approach 1:
The biasing magnet is designed with a height that is less than the height of the magnetoresistive stack, creating a non-uniform magnetic bias field that is concentrated in specific regions. This local quality approach allows the bias field to be applied where most needed (at the media interface) without extending through the entire stack height, thereby reducing unnecessary magnetic noise while maintaining the benefits of partial biasing for signal enhancement.
2Reliability
If full magnetic biasing is applied to the magnetoresistive stack, then the signal amplitude increases, but the magnetic noise and reader resistance increase
Solution Approach 1:
The patent implements partial magnetic biasing where the biasing magnet height is intentionally made less than the magnetoresistive stack height. This partial action provides sufficient magnetic bias to enhance the read signal amplitude from the magnetic media while avoiding the application of excessive bias field throughout the entire stack, thereby preventing the generation of unnecessary magnetic noise and keeping reader resistance at acceptable levels.
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
This configuration enhances the signal-to-noise ratio and reduces magnetic noise, allowing for higher areal density and improved data recovery without increasing reader resistance, even at high recording densities beyond 1 Tb/in2.
Implementation Method 1
a biasing magnet positioned adjacent the magnetoresistive stack
Implementation Method 2
magnetoresistive stack
Data Source
AI summary
Various embodiments can be generally directed to a magnetoresistive stack with a first stripe height and a biasing magnet positioned adjacent the magnetoresistive stack. The biasing magnet can have a second stripe height that is less than the first stripe height. The first and second stripe heights may correspond to a minimum signal to noise ratio in the magnetoresistive stack.