Embedded Contact Sensor Domain Pinning for Magnetic Noise Reduction
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Solution Overview
Problem
Magnetic data recording systems face challenges in accurately detecting head disk contact due to extreme signal noise from magnetic fields, which can lead to false positives and damage to the magnetic sensor and media.
Innovation Solution
An embedded contact sensor with a thermoresistive layer and a domain pinning structure, either using hard magnetic materials or antiferromagnetic layers, to prevent magnetic domain movement and reduce signal noise, ensuring the sensor only responds to head disk contact-induced heat spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an embedded contact sensor is incorporated to monitor head-disk spacing, then head disk contact detection capability is improved, but signal noise from magnetic fields increases causing false positives
Solution Approach 1:
The patent converts the harmful magnetic field sensitivity into a beneficial feature by using a magnetoresistive sensor that is initially sensitive to magnetic fields. The domain pinning structure then controls this sensitivity to respond only to contact-induced magnetic field changes, transforming the noise problem into a selective detection capability
Solution Approach 2:
The patent changes the magnetic domain state parameters by introducing domain pinning structures that fix the magnetization direction of the thermoresistive layer. This parameter change prevents spontaneous domain fluctuations and makes the sensor response dependent only on contact-induced heating, not ambient magnetic field variations
2Productivity
If magnetic spacing between read/write heads and magnetic medium is minimized to maximize performance, then system performance is improved, but probability of head disk contact increases
Solution Approach 1:
The patent performs preliminary detection of head-disk contact conditions using the embedded sensor before actual contact damage can occur. The domain pinning structure ensures the sensor reliably detects contact events, allowing preliminary protective actions to be taken before catastrophic failure
3Measurement precision
If extreme signal noise from magnetic media is present, then false contact detections occur, but damage to magnetic sensor and media results
Solution Approach 1:
The patent introduces domain pinning structures as intermediary elements between the thermoresistive layer and external magnetic fields. These pinning structures act as a mediator that blocks unwanted magnetic domain fluctuations while allowing the sensor to detect contact-induced thermal effects, filtering out false signals
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 effectively reduces signal noise and prevents false contact detections, enhancing the accuracy of head disk contact monitoring and minimizing damage to the magnetic sensor and media.
Implementation Method 1
an embedded contact sensor that includes a thermoresistive layer
Implementation Method 2
a structure for pinning magnetic domains in the thermoresistive layer
Data Source
AI summary
A head for magnetic data recording that includes an embedded contact sensor. The embedded contact sensor detects head disk contact by detecting changes in temperature as a result of contact between the head and the disk. The embedded contact sensor includes a thermoresistive layer and a structure for pinning the magnetic domains of the thermoresistive layer. This pinning of the magnetic domains prevents the thermoresistive layer from changing resistance in response to magnetic fields (rather than temperature) so as to avoid unwanted signal noise as a result of a magnetic signal from the magnetic media.