SOT Temperature Sensor for HAMR Head Height Control
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Solution Overview
Problem
Current temperature detection methods in hard disk drives, such as thermal fly-height control (TFC), face inefficiencies due to thermal expansion and protrusion issues, necessitating an improved temperature monitoring system for precise head-disk spacing and reliability in energy-assisted magnetic recording technologies like HAMR and MAMR.
Innovation Solution
A temperature detection device comprising an antiferromagnetic (AFM) layer, a ferromagnetic (FM) layer, and a spin-orbit torque (SOT) material layer, utilizing the spin Seebeck effect and inverse spin Hall effect to generate a voltage signal for accurate temperature monitoring, which can be used to regulate flying height and enhance recording head reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If thermal fly-height control (TFC) is used to intentionally induce expansion of the recording head to reduce spacing between head and disk, then the spacing control is improved, but thermal expansion causes inaccurate spacing control and may result in destructive head/disk interactions
Solution Approach 1:
The patent implements a feedback mechanism by placing a temperature sensor on the recording head that continuously monitors head temperature and sends signals to the TFC controller. This feedback loop allows the system to adjust heating elements in real-time to achieve precise fly-height control while preventing thermal expansion that would cause harmful head-disk contact, thus resolving the contradiction between spacing control and safety
Solution Approach 2:
The patent replaces traditional mechanical or purely thermal control mechanisms with a sensor-based detection and control system. By using temperature sensors to detect head temperature and electronically controlling the heating elements, the system achieves more precise and reliable fly-height control without the inaccuracies and safety issues of purely mechanical or unmonitored thermal expansion methods
2Measurement precision
If head temperature monitoring is implemented using existing methods, then temperature detection is achieved, but thermal expansion and protrusion issues reduce detection accuracy and control efficiency
Solution Approach 1:
The patent merges the temperature sensing function directly into the recording head structure by integrating temperature sensors onto the head assembly. This consolidation allows the same component to serve dual purposes: recording data and monitoring temperature, thereby improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The recording head monitors its own temperature through integrated sensors, enabling self-diagnosis and self-regulation. This self-service approach allows the head to detect its thermal state and trigger appropriate control responses without requiring external monitoring systems, improving accuracy while maintaining simplicity
3Productivity
If energy assisted magnetic recording (HAMR or MAMR) is used to aid recording, then recording capacity is improved, but injection of assistive energy causes head expansion and protrusion toward the disk
Solution Approach 1:
The patent uses temperature sensors to continuously monitor head temperature during energy-assisted magnetic recording operations. When the temperature reaches thresholds that would cause harmful protrusion, the system automatically reduces or stops the injection of assistive energy, thereby maintaining high recording capacity while preventing excessive head expansion and protrusion
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 proposed solution effectively monitors temperature changes, improving flying height control and recording head reliability by generating a measurable voltage signal, thus addressing inefficiencies in existing TFC systems and enhancing the performance of energy-assisted magnetic recording technologies.
Implementation Method 1
spin-orbit torque (SOT) layered device for measuring temperature based on the spin Seebeck effect
Implementation Method 2
based on the spin Seebeck effect and the associated inverse spin Hall effect
Data Source
AI summary
The present disclosure generally relates to temperature detection devices, comprising an antiferromagnetic (AFM) layer a ferromagnetic (FM) layer disposed on the AFM layer and a spin-orbit torque (SOT) material layer disposed on the FM layer. The SOT material layer may comprise: a SOT material portion; a SOT material portion and an insulating material portion; or a plurality of SOT material portions and a plurality of insulating material portions. The temperature detection devices may also have a second FM layer disposed on the SOT material layer. The temperature detection devices may also have a second AFM layer disposed on the second FM layer. In another embodiment, the temperature detection devices may also have a heat sink.