Dependence of optical laser power on disk radius, head-disk spacing and media properties in heat-assisted magnetic recording

2020 ◽  
Vol 26 (11) ◽  
pp. 3371-3376
Author(s):  
Tan D. Trinh ◽  
Sukumar Rajauria ◽  
Robert Smith ◽  
Erhard Schreck ◽  
Qing Dai ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Laser Power ◽  
Disk Radius ◽  
Heat Assisted Magnetic Recording ◽  
Optical Laser ◽  
Disk Spacing

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.

Study of Recorded Mark Width Change with Laser Power in Heat-Assisted Magnetic Recording

2009 ◽  
Vol 48 (3) ◽  
pp. 03A058
Author(s):  
Baoxi Xu ◽  
Hongxing Yuan ◽  
Sofian MD ◽  
Rong Ji ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Laser Power ◽  
Heat Assisted Magnetic Recording ◽  
Width Change

Disk Protrusion Measurement in a Back-Heating Study for Heat Assisted Magnetic Recording

2020 ◽  
Author(s):  
Shaomin Xiong ◽  
Robert Smith ◽  
Erhard Schreck
Keyword(s):  
Heat Transfer ◽  
Magnetic Recording ◽  
Local Heating ◽  
Hard Disk Drives ◽  
Detection Sensitivity ◽  
Experimental Setup ◽  
Heat Assisted Magnetic Recording ◽  
Management Scheme ◽  
The Media ◽  
Disk Spacing

Abstract Heat assisted magnetic recording (HAMR) is a promising technology for the next generation hard disk drives (HDDs). Understanding the heat transfer at nanoscales and implementing a proper thermal management scheme become very critical as a few heat sources and energy delivery components are compactly integrated in a HAMR drive. Recently, a back-heating experimental setup is used to study heat transfer behavior. It is found that the detection of head disk contact and head disk spacing control become more complicated in this experimental setup because the local heating generates a protrusion on the media surface. In this paper, we demonstrate a method to enhance the contact detection sensitivity significantly by modulating the head disk spacing. It shows that a light contact between the head TFC protrusion and media protrusion can be effectively detected. Thereafter, the media protrusion can be measured and the head disk spacing can be well set.

Investigation of the Local Temperature Increase From the Magnetization Decay for Heat Assisted Magnetic Recording

2013 ◽  
Author(s):  
Shaomin Xiong ◽  
David Bogy
Keyword(s):  
Refractive Index ◽  
Magnetic Recording ◽  
Curie Point ◽  
Laser Heating ◽  
Temperature Increase ◽  
Laser Power ◽  
Local Temperature ◽  
Thermally Stable ◽  
Heat Assisted Magnetic Recording ◽  
The Media

The areal data density of magnetic recording hard disk drives (HDDs) increases year by year, following a trend similar to Moore’s law. However, the increase is not unbounded and there are some physical limits. As the density increases, the size of each magnetic grain shrinks. Finally the magnetic grain will be no longer thermally stable due to what is termed superparamagnetism. Above this point, the magnetic storage would be not reliable because the magnetic grains’ orientations fluctuate randomly. To increase magnetic recording density to more than 1 Tb/in2 and break this limit, heat assisted magnetic recording (HAMR) is proposed. In HAMR systems, a more thermally stable magnetic material, one with higher coercivity, will be used as a recording layer. But the coercivity of this material at room temperature is so high that it is difficult for the writer to switch the magnetic orientation with current magnetic transducers. However, the coercivity drops sharply if the temperature is raised close to the Curie temperature. In HAMR systems, a laser is proposed as the means to heat the disk to the Curie point. Simultaneously the magnetic field is applied from the writer to switch the magnetic bits. The success of the magnetic switching is very sensitive to the media temperature [2]. If the temperature is too low compared with the Curie point, it will not be able to write any information into the media. Conversely, heating the media over the Curie point requires more energy and may bring a greater challenge for the head disk interface (HDI). It is very important to understand the local temperature distribution during the laser heating and to calibrate the laser power input for HAMR writing. Some work has been done to evaluate the temperature increase using both numerical and experimental methods [3, 4]. Tagawa et.al. observed the disk refractive index change during laser heating and compared it with the change under conventional oven heating. This is a good method to calibrate the laser power and get the average temperature but it has some limitations for getting the accurate temperature distributions because of the averaging effect for the refractive index measurement by ellipsometry.

Simulation of magnetic footprints for heat assisted magnetic recording

2017 ◽  
Vol 78 (2) ◽  
pp. 20301
Author(s):  
Kotchakorn Pituso ◽  
Pirat Khunkitti ◽  
Anan Kruesubthaworn ◽  
Komkrit Chooruang ◽  
Damrongsak Tongsomporn ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Heat Assisted Magnetic Recording

A multi-functional testing instrument for heat assisted magnetic recording media

2014 ◽  
Vol 115 (17) ◽  
pp. 17B726 ◽  
Author(s):  
H. Z. Yang ◽  
Y. J. Chen ◽  
S. H. Leong ◽  
C. W. An ◽  
K. D. Ye ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Recording Media ◽  
Functional Testing ◽  
Magnetic Recording Media ◽  
Testing Instrument ◽  
Heat Assisted Magnetic Recording

Effect of Molecular Weight on Lubricant Depletion in a Heat Assisted Magnetic Recording System

2017 ◽  
Author(s):  
Deng Pan ◽  
Wenping Song
Keyword(s):  
Molecular Dynamics ◽  
Molecular Weight ◽  
Molecular Dynamics Simulation ◽  
Magnetic Recording ◽  
Recording System ◽  
Dynamics Simulation ◽  
Disk System ◽  
Heat Assisted Magnetic Recording ◽  
Lubricant Depletion

A model for studying lubricant depletion in HAMR slider/disk system was developed based on molecular dynamics simulation. We found that the lubricant molecular weight has small effect on lubricant depletion.

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