Experimental Study of Nanoscale Head-Disk Heat Transfer In Heat-Assisted Magnetic Recording

2021 ◽  
Author(s):  
Qilong Cheng ◽  
David B. Bogy
Keyword(s):  
Heat Transfer ◽  
Silicon Wafer ◽  
Magnetic Recording ◽  
Laser Exposure ◽  
Heat Assisted Magnetic Recording ◽  
Contact Sensor ◽  
Higher Temperature ◽  
Dc Current ◽  
Fly Height ◽  
Head Temperature

Abstract To study the nanoscale heat transfer and laser-related protrusions in heat-assisted magnetic recording (HAMR), we performed static touchdown experiments between HAMR waveguide heads and non-rotating media such as a silicon wafer and a recording disk with an AlMg substrate. During the static touchdown, the laser element is energized with DC current and the embedded contact sensor (ECS) is used to monitor the head temperature. The experimental results show that the thermal fly-height control (TFC) touchdown power decreases with increasing laser current. Meanwhile, the head temperature increases due to the laser heating. From this the ECS resistance rise induced by the laser is extracted. The results show that the silicon wafer dissipates heat effectively under the laser exposure, while the AlMg-substrate disk undergoes a higher temperature rise, which in turn heats the head.

A Heat Transfer Study in the Head Disk Interface and an Insight to Heat Assisted Magnetic Recording Design

2017 ◽  
Author(s):  
Haoyu Wu ◽  
David Bogy
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Convective Heat Transfer Coefficient ◽  
Head Disk Interface ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
Height Control ◽  
Contact Sensor ◽  
Series Of Experiments ◽  
Fly Height

Understanding the heat transfer in the head disk interface (HDI) in the heat assisted magnetic recording (HAMR) is important. In this paper, we report on a series of experiments to study the heat transfer in the HDI using the perpendicular magnetic recording (PMR) heads and media. The temperature increase of the embedded contact sensor (ECS) and the thermal fly-height control (TFC) heater was compared in the fly setup and non-fly setup. A series of simulations were performed to explain the results. We show that the design of the air bearing surface can significantly affect the pressure distribution in the read/write transducer area, and thereby affect the convective heat transfer coefficient.

Numerical and Experimental Investigation of Nanoscale Heat Transfer in the Head-Media Interface During Static Touchdown

2019 ◽  
Author(s):  
Siddhesh V. Sakhalkar ◽  
Qilong Cheng ◽  
Yuan Ma ◽  
Amin Ghafari ◽  
David B. Bogy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Magnetic Recording ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Nanoscale Heat Transfer ◽  
Fly Height ◽  
Head Temperature

Abstract With minimum fly height of less than 10 nm in contemporary hard-disk drives, understanding nanoscale heat transfer at the head-media interface is crucial for developing reliable head and media designs. Particularly, with the emergence of Heat-Assisted Magnetic Recording (HAMR) and Microwave-Assisted Magnetic Recording (MAMR), head failure due to overheating has become an increasing concern. There is a need to develop a methodology to use theoretical curves for spacing-dependent nanoscale heat transfer coefficient to predict head and media temperatures in actual hard disk drives. In this study, we present a numerical model to simulate the head and media temperature profiles during static touchdown and compare our results with experiments performed with a magnetic head on a silicon wafer. As the head approaches touchdown with increasing TFC power, the phonon conduction heat transfer coefficient between the head and the substrate increases exponentially, causing a drop in the head temperature vs TFC power curve. Our model shows that the introduction of van der Waals forces between the head and the substrate causes a steeper drop in the head temperature curve and ensures a good quantitative match with experimental results.

Head Disk Spacing Effect on Heat Transfer in Heat Assisted Magnetic Recording

2017 ◽  
Author(s):  
Shaomin Xiong ◽  
Erhard Schreck ◽  
Sripathi Canchi
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Spacing Effect ◽  
Disk Drive ◽  
Heat Assisted Magnetic Recording ◽  
Heating Source ◽  
Spacing Effects ◽  
Thermal Sensing ◽  
Transfer Mechanisms ◽  
Disk Spacing

Heat transfer at nanometer scale attracts a lot of interest from both academia and industries. The hard disk drive (HDD) industry cares about the heat transfer between the head and disk, as several heating and thermal sensing elements are integrated into the HDD system. Understanding the heat transfer mechanism and its dependency on spacing becomes very critical for heat assisted magnetic recording (HAMR). In this paper, we propose a new method to study the head disk spacing effects on heat transfer by introducing a small perturbation to the spacing while maintaining the heating source unchanged. The dependency of heat transfer on the nanoscale spacing provides insights to the understanding of heat transfer mechanisms inside the nanoscale gap.

A Numerical Study of the Nanoscale Heat Transfer in the Head-Disk Interface for Heat Assisted Magnetic Recording

2016 ◽  
Author(s):  
Haoyu Wu ◽  
David Bogy
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Transfer Problem ◽  
Numerical Study ◽  
Near Field ◽  
Experimental Result ◽  
Head Disk Interface ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
Nanoscale Heat Transfer

The near field transducer (NFT) overheating problem is an issue the hard disk drive (HDD) industry has faced since heat-assisted magnetic recording (HAMR) technology was first introduced. In this paper, a numerical study of the head disk interface (HDI) is performed to predict the significance of the nanoscale heat transfer due to the back heating from the disk. A steady-state heat transfer problem is first solved to get the disk temperature profile. Then an iterative simulation of the entire HDI system is performed. It shows that the heat transfer coefficient in the HDI increases to about 6:49 × 106 W/(m2K) when the clearance is 0:83 nm. It also shows that in the free space laser scenario, the simulation result is close to the experimental result.

A Numerical Investigation of the Nanoscale Heat Transfer in Heat Assisted Magnetic Recording

2017 ◽  
Author(s):  
Yueqiang Hu ◽  
Haoyu Wu ◽  
Yonggang Meng ◽  
David Bogy
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Near Field ◽  
Field Analysis ◽  
Management Problem ◽  
Heat Management ◽  
Heat Assisted Magnetic Recording ◽  
The Media ◽  
Em Field

The heat management problem in the heat assisted magnetic recording (HAMR) has been a long-term issue. In this paper, we investigated the temperature increase of a “lollipop” type near field transducer (NFT) in HAMR. We included the electromagnetic (EM) field analysis in the modeling and considered the back-heating from the media to the head with various heat transfer mechanisms. The results showed that the overcoat layer of the NFT plays an important role for protecting the NFT from high temperature. Degradation of the overcoat layer may result in the early failure of the NFT.

Nanoscale heat transfer in the head-disk interface for heat assisted magnetic recording

2016 ◽  
Vol 108 (9) ◽  
pp. 093106 ◽  
Author(s):  
Haoyu Wu ◽  
Shaomin Xiong ◽  
Sripathi Canchi ◽  
Erhard Schreck ◽  
David Bogy
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Head Disk Interface ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
Nanoscale Heat Transfer
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