Material Transfer From Media to Head in Heat Assisted Magnetic Recording (HAMR)

2021 ◽  
Author(s):  
Shaomin Xiong ◽  
Robert Smith ◽  
Qing Dai ◽  
Erhard Schreck
Keyword(s):  
Magnetic Recording ◽  
Thermal Gradient ◽  
High Coercivity ◽  
Magnetic Head ◽  
Material Transfer ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
The Media ◽  
Change Material ◽  
Very High

Abstract Heat assisted magnetic recording (HAMR) is one of the leading technologies for next generation magnetic recording. Laser heating is utilized in HAMR to achieve magnetic writing of the very high coercivity media. However, the high temperature environment creates several reliability challenges for the head disk interface (HDI). Material transfer within the HDI under HAMR conditions or emulated HAMR conditions has been studied by experiments and simulations. It is found that the material transfer is mainly driven by thermal gradient and mechanical interaction such as head disk contact. In this paper, we designed an experiment to investigate the material transfer from HAMR media to a flying magnetic head. It shows that thermal gradient, more specifically a hotter media and cooler head, is the driving force for the material accumulation on the head. Furthermore, we calibrated the media temperature by a phase change material to identify the critical temperature that triggers the material transfer process. This study is important to understand the smear formation mechanism in HAMR drives.

Material Transfer Inside Head Disk Interface for Heat Assisted Magnetic Recording

2017 ◽  
Vol 65 (2) ◽  
Author(s):  
Shaomin Xiong ◽  
Na Wang ◽  
Robert Smith ◽  
Dongbo Li ◽  
Erhard Schreck ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Head Disk Interface ◽  
Material Transfer ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface

Head–Disk Interface Materials Issues in Heat-Assisted Magnetic Recording

2014 ◽  
Vol 50 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Bruno Marchon ◽  
Xing-Cai Guo ◽  
Bala Krishna Pathem ◽  
Franck Rose ◽  
Qing Dai ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Head Disk Interface ◽  
Heat Assisted Magnetic Recording ◽  
Disk Interface ◽  
Interface Materials

Transient Thermal Response of the Media by Free Space Laser Heating in Heat Assisted Magnetic Recording

2016 ◽  
Author(s):  
Shaomin Xiong ◽  
Robert Smith ◽  
Na Wang ◽  
Dongbo Li ◽  
Erhard Schreck ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Heat Conduction Problem ◽  
Temperature Response ◽  
Thermal Response ◽  
Areal Density ◽  
Heat Assisted Magnetic Recording ◽  
Lumped Model ◽  
The Media ◽  
Transient Thermal ◽  
Transient Thermal Response

Heat assisted magnetic recording (HAMR) promises to deliver higher storage areal density than the current perpendicular magnetic recording (PMR) product. A laser is introduced to the HAMR system to heat the high coercively magnetic media above the Curie temperature (Tc) which is as high as 750 K in order to enable magnetic writing. The thermal response of the media becomes very critical for the success of the data writing process. In this paper, a new method is proposed to understand the transient thermal behavior of the HAMR media. The temperature response of the media is measured based on thermal erasure of the magnetically written signal. A lumped model is built to simplify the heat conduction problem to understand the transient thermal response. Finite element modeling (FEM) is implemented to simulate the transient thermal response of the media due to the laser pulse heating. The experimental and simulation results show fairly good agreement.

Experimental Study on Laser-Induced Protrusion in Heat-Assisted Magnetic Recording

2020 ◽  
Author(s):  
Qilong Cheng ◽  
Haoyu Wang ◽  
Siddhesh V. Sakhalkar ◽  
David B. Bogy
Keyword(s):  
Magnetic Recording ◽  
Laser Heating ◽  
Hot Spot ◽  
Magnetic Layer ◽  
Optical Power ◽  
Linear Velocity ◽  
Component Level ◽  
Heat Assisted Magnetic Recording ◽  
Power Change ◽  
The Media

Abstract In heat-assisted magnetic recording (HAMR), a laser is introduced to create a hot spot on the media and locally heat the magnetic layer to its Curie temperature. Besides the optical power that the laser provides to the media, thermal energy diffuses inside the slider and induces an extra protrusion, which is called laser-induced protrusion (LIP). The LIP needs to be considered and compensated during flying in the HAMR conditions. In this study, we focus on long timescale (milliseconds) of laser heating during the flying condition. When the laser is switched from OFF to ON, the touchdown power, indicated by an acoustic emission (AE) sensor, decreases due to spacing loss and the touchdown power change (ΔTDP) is used as the measure of the LIP. A component-level spinstand stage for HAMR heads and media is used to study the LIP as a function of laser-on time, laser current and linear velocity. Our experimental results show that it takes around 20 ms for the LIP to reach steady state and the protrusion size is proportional to the square of laser current. As the operating linear velocity increases from 12 m/s to 24 m/s, the LIP decreases by approximately 52%.

Effects of Varied Physical Mechanisms on the Evolution of Lubricant Interface During Heat-Assisted Magnetic Recording

2013 ◽  
Author(s):  
Ajaykumar Rajasekharan
Keyword(s):  
Magnetic Recording ◽  
Air Bearing ◽  
Complex Interplay ◽  
Heat Assisted Magnetic Recording ◽  
Physical Mechanisms ◽  
Capillary Stress ◽  
Vapor Recoil ◽  
The Media ◽  
Physical Effects ◽  
Pfpe Lubricants

A concoction of various forces and physical effects (both mechanical and chemical) come into play in the depletion and evolution of the lubricant on the media during a heat-assisted magnetic recording (HAMR) process. They include the air-bearing shear and pressure, capillary pressure, thermo-capillary stress, disjoining pressure, lubricant desorption and the vapor recoil mechanism. The effects of these mechanisms and their complex interplay to stabilize/destabilize the lubricant interface is studied here numerically. Results for Z-type perfluropolyether (PFPE) lubricants with different polydispersity indices (PDI) are summarized.

Effect of Recording Conditions on the Downtrack Thermal Gradient in Heat-Assisted Magnetic Recording

2018 ◽  
Vol 54 (11) ◽  
pp. 1-4 ◽  
Author(s):  
Stephanie Hernandez ◽  
Zengyuan Liu ◽  
Steven Granz ◽  
Ian Gilbert ◽  
Drew Mader ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Thermal Gradient ◽  
Heat Assisted Magnetic Recording ◽  
Recording Conditions

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.

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