MAMR Head Structure with Asymmetric Electrode Protection
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Solution Overview
Problem
The breakdown of spin-torque oscillators (STOs) in hard disk drives (HDDs) using microwave assisted magnetic recording (MAMR) technology due to large currents flowing through them during head/disk contact is a significant issue, leading to potential system failure.
Innovation Solution
The implementation of a magnetic head slider with two electrodes, where one electrode has a higher potential than the other, and a preamplifier is used to direct current flow from the higher potential electrode to the disk, thereby avoiding current flow through the STO, thus preventing breakdown. This configuration includes a thin film section on the slider with the STO and electrodes, and a grounded disk spindle for resistance, ensuring the higher potential electrode protrudes closer to the disk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current flows through the STO during head/disk contact, then magnetic recording function is maintained, but STO breakdown occurs due to large current
Solution Approach 1:
The patent introduces a sacrificial electrode as an intermediary element between the STO and the disk. This electrode is positioned closer to the disk surface and is designed to contact the disk first, thereby intercepting and diverting the large contact current away from the STO. The sacrificial electrode acts as a protective mediator that absorbs the harmful electrical stress, preventing it from reaching and damaging the STO while allowing the magnetic recording function to continue operating normally.
2Productivity
If fly-height is reduced to increase storage density, then recording density increases, but head/disk contact probability increases causing STO breakdown
Solution Approach 1:
The patent implements a sacrificial electrode that is positioned closer to the disk surface than the STO, creating a protective buffer zone. This electrode serves as a predetermined sacrificial element that will contact the disk first during any head/disk contact events, thereby cushioning and absorbing the electrical冲击 before it can reach the STO. This beforehand cushioning mechanism allows the system to operate at reduced fly-heights for higher storage density while maintaining STO reliability through the protective barrier.
3Reliability
If electrode positioning is adjusted to prevent STO contact, then STO protection is achieved, but current path must be redirected
Solution Approach 1:
The patent employs asymmetric electrode positioning where the sacrificial electrode is deliberately placed at a different height relative to the disk surface compared to the STO electrode. Specifically, the sacrificial electrode is positioned closer to the disk, creating an asymmetric configuration that naturally guides the current path away from the STO during contact events. This asymmetric design simplifies the overall structure by using geometric positioning rather than complex active control mechanisms to achieve current path redirection and STO protection.
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 solution effectively prevents STO breakdown by ensuring current flows directly from the higher potential electrode to the disk, reducing the risk of electrical damage and enhancing the reliability of HDDs with MAMR technology.
Implementation Method 1
A preamplifier is adapted to send a current through the two electrodes, resulting in the higher potential electrode protruding closer to the disk than the lower potential electrode. Current then flows from one electrode to the disk without flowing through the STO
Implementation Method 2
MAMR technology performs magnetic recording using a microwave assisted effect generated by a STO incorporated in the head slider
Data Source
AI summary
Embodiments disclosed herein generally relate to the data storage field and hard disk drives (HDD) using microwave assisted magnetic recording (MAMR) technology. Aspects of the preferred embodiments are to prevent the breakdown of spin torque oscillators (STO) due to large amounts of current flowing through the STO during head/disk contact. A magnetic head slider is disposed above and spaced apart from a disk. A STO is formed on a section of the magnetic head slider. Two electrodes are coupled to the STO, and one electrode has a higher potential than the other electrode. A preamplifier is adapted to send a current through the two electrodes, resulting in the higher potential electrode protruding closer to the disk than the lower potential electrode. Current then flows from one electrode to the disk without flowing through the STO, and breakdown of the STO is prevented.