Lubricant reflow after laser heating in heat assisted magnetic recording

Wu, Huan; Rodriguez-Mendez, Alejandro; Xiong, Shanxin; Bogy, David B.

doi:10.1063/1.4914073

Cited by 14 publications

(3 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For this reason, Dahl et al [24] carried out a detailed parameter study of the effect of each factor on lubricant depletion groove caused by laser heating using the diffusion equation, which takes into account disjoining pressure, temperature characteristics of surface tension, heated evaporation, temperature and film thickness effects on viscosity, etc. On the other hand, Wu et al [25] measured the replenishment process of the depleted groove produced by laser for Z-tetraol lubricant with thickness of 0.98 nm and bonded ratio of 0.6 and compared it with the calculated results using the conventional Equation (3) with d 0 = 0, A = 10 −21 J/m 2 , and µ m = 1.5 Pa•s. The replenishment speed appears to be close to the experimental value, but this may be due to the fact that the lubricating film had a small bonded ratio and the extremely small Hamaker constant was used.…”

Section: Diffusion Characteristics Of Sub-nanometer Lubricant Filmmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

View full text Add to dashboard Cite

This review presents a series of studies which have demonstrated that the diffusion characteristics of rarefied mobile lubricant films used in modern magnetic disks can be evaluated by a novel diffusion theory based on continuum mechanics, and that the meniscus force of the rarefied film is the major interaction force at the head-disk interface. The limitations of the conventional diffusion and disjoining pressure equations are first shown, and diffusion and disjoining pressure equations for rarefied liquid films are proposed, showing that the diffusion coefficient is in good agreement with the experiment. The experiment, in which glass spheres with radii of 1 and 2 mm collided with magnetic disks of different film thicknesses, showed that attraction similar to the pull-off forces of a static meniscus was measured only at the separation. Furthermore, mathematical analysis of the elastic meniscus contact between a sphere and a plane with a submonolayer liquid film showed that the maximum adhesion force is equal to the meniscus pull-off force and that the contact characteristics become similar to those of the JKR theory as the liquid film thickness decreases. A basic physical model of submonolayer liquid film is also proposed to justify the continuum mathematical equations.

show abstract

Section: Diffusion Characteristics Of Sub-nanometer Lubricant Filmmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

View full text Add to dashboard Cite

show abstract

“…Salah satu tantangan penggunaan PMA adalah meminimalkan medan magnet tulisan karena koersivitasnya yang tinggi. Penggunaan pulsa laser untuk menghasilkan panas pada area media yang terlokalisasi memainkan peran penting untuk mengurangi koersivitas ini (Wu et al, 2015). Pemanasan lokal menyebabkan ketidakteraturan magnetisasi yang memunculkan istilah probabilitas pembalikan.…”

Section: Pendahuluanunclassified

Dinamika Pembalikan Magnetisasi Nanoblock Berbasis Kobalt Teredam Kuat di Bawah Stimulasi Medan Panas

Wibowo

Riyanto²

2023

juses

View full text Add to dashboard Cite

Dinamika pembalikan magnetisasi pada nanoblock berbasis kobalt teredam kuat yang distimulasi oleh pemanasan pulsa telah dieksplorasi secara numerik untuk model parallelepiped dengan ukuran 50×50×20 nm3. Pengaturan simulasi diimplementasikan untuk mengevaluasi dua parameter penting dalam perekaman magnetik dengan bantuan panas, yaitu stabilitas termal, dan konsumsi medan tulis. Stabilitas termal diukur melalui medan magnet induksi yang meningkat secara linear hingga 2 Tesla selama 2,5 ns pada kesetimbangan termal terhadap lingkungan. Dalam simulasi sistem dengan stimulasi medan panas, konsumsi medan tulis diselidiki menggunakan dua jenis pulsa, yaitu medan magnet, dan pulsa medan termal. Simulasi ini didasarkan pada persamaan Landau-Lifshift-Gilbert yang memasukkan teorema disipasi fluktuasi dalam menghitung efek fluktuasi termal. Selain itu, parameter-parameter material yang tergantung suhu, yaitu saturasi magnetik, anisotropi magnetik, dan interaksi pertukaran, juga diperhitungkan. Sebagai hasilnya, nanoblock berbasis kobalt yang teredam kuat memiliki penghalang energi magnetik yang tinggi untuk mencegah batasan superparamagnetik. Selain itu, medan penulisan dapat dikontrol melalui pengaturan periode pemanasan, dan juga melalui manipulasi sifat magnetik seperti redaman magnetik intrinsik.

show abstract

“…The diamond-like carbon (DLC) protective film and perfluoropolyether (PFPE) lubricant film of the disk are heated to high temperatures reaching 200-500°C, which causes damage such as evaporation, thermal decomposition, and thermal oxidation. However, considering that the application of highcapacity disks using HAMR technology is storage for near-line data servers such as cloud computing, this is not considered to be a major problem because most of it is a write-once usage mode, and the damaged lubricating film is repaired in a short time [2,3]. In contrast, evaporated and thermally decomposed lubricant and DLC-derived head smears adhere to the magnetic head slider surface owing to heating [4,5], causing more serious problems for hard disks, such as head slider vibration and troublesome effects on read/write elements.…”

Section: Introductionmentioning

confidence: 99%

Effects of Oxygen on Smear Formation in Heat Assisted Magnetic Recording System

et al. 2022

View full text Add to dashboard Cite

Heat-assisted magnetic recording (HAMR) is expected to be a realistic next-generation technology for increasing the recording density of hard disks. However, the magnetic layer is heated above the Curie temperature, and, as a result, the heated lubricant is desorbed from the disk by decomposition and evaporation, which causes a problem as it adheres to the air-bearing surface (ABS) as a smear. In this study, pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) analysis was performed in helium and air environments to investigate the decomposition mechanism of perfluoropolyether (PFPE) lubricant D-4OH by heating and in the presence of oxygen. In the helium environment, thermal decomposition of the end groups was confirmed at 350°C and above with a possibility of main chain decomposition at 450°C. In the air environment, decomposition of the end group was confirmed at 250°C and above, and decomposition of the main chain was confirmed at 450°C. Experiments using a pin-on-disk tester were conducted to confirm what happens to the area of smear when a thin film of D-4OH lubricant coated on an actual disk is laser heated. As a result, it was confirmed that the area of smear decreased even at an oxygen concentration of 5%.

show abstract

Lubricant reflow after laser heating in heat assisted magnetic recording

Abstract: Effect of gradient alignment in heat assisted magnetic recording J. Appl. Phys. 105, 07B905 (2009); 10.1063/1.3073948 Effect of various physical factors on thin lubricant film migration on the flying head slider at the head-disk interface of hard disk drives

Cited by 14 publications

References 8 publications

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Dinamika Pembalikan Magnetisasi Nanoblock Berbasis Kobalt Teredam Kuat di Bawah Stimulasi Medan Panas

Effects of Oxygen on Smear Formation in Heat Assisted Magnetic Recording System

Contact Info

Product

Resources

About