Experimental and FEA Scratch of Magnetic Storage Thin-Film Disks to Correlate Magnetic Signal Degradation With Permanent Deformation

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Sung-Chang Lee ◽  
Mike Suk
Keyword(s):  
Thin Film ◽  
Magnetic Recording ◽  
Permanent Deformation ◽  
Disk Drive ◽  
Magnetic Storage ◽  
Magnetic Signal ◽  
Element Analysis ◽  
Recording Layer ◽  
Signal Degradation ◽  
Extent Of Damage

Scratch-related magnetic signal degradation can occur during magnetic storage hard disk drive operations when the read-write heads contact the spinning multilayer disks. To investigate this phenomenon, controlled nanoscratch experiments were performed on perpendicular magnetic recording media using various indenters of different radii of curvature. Various loading conditions were used to cause permanent scratches that were measured using atomic force microscopy. The nanoscratch experiments were simulated using finite element analysis (FEA) that included the detailed nanometer scale thin-film multilayer mechanical properties. The permanently deformed field in the subsurface magnetic recording layer was extracted from the FEA results. The residual scratch widths measured on the surface of the magnetic storage disk were directly compared with the residual subsurface widths of the region on the magnetic recording layer, where extensive permanent lateral deformation was present. It was found that the subsurface widths of the deformed regions were significantly larger than the surface scratch widths. Thus, subsurface thin-film layers, such as the magnetic recording layer, could be damaged without observable damage to the protective top surface carbon overcoat. The exact location and extent of damage to the magnetic recording layer depends on the scratch load, size of scratch tip, and the friction at the interface. Such permanent deformation in magnetic recording layer could lead to demagnetization, which has been reported in the literature.

Experimental and FEA Scratch Correlation of Magnetic Signal Degradation in Magnetic Storage Thin-Film Disks

2009 ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Sung-Chang Lee ◽  
Mike Suk
Keyword(s):  
Thin Film ◽  
Magnetic Recording ◽  
Permanent Deformation ◽  
Disk Drive ◽  
Magnetic Storage ◽  
Magnetic Signal ◽  
Element Analysis ◽  
Recording Layer ◽  
Signal Degradation ◽  
Extent Of Damage

Scratch-related magnetic signal degradation can occur during magnetic storage hard disk drive operation when the read-write heads contact the spinning multilayer disks. To investigate this phenomenon controlled nanoscratch experiments were performed on perpendicular magnetic recording media using various indenters of different radii of curvature. Various loading conditions were used to cause permanent scratches that were measured using atomic force microscopy. The nanoscratch experiments were simulated using finite element analysis (FEA) that included the detailed nanometer scale thin-film multilayer mechanical properties. The permanently deformed field in the sub-surface magnetic recording layer was extracted from the FEA results. The residual scratch widths measured on the surface of the magnetic storage disk were directly compared with the residual sub-surface widths of the region on the magnetic recording layer where extensive permanent lateral deformation was present. It was found that the sub-surface widths of the deformed regions were significantly larger than the surface scratch widths. Thus, sub-surface thin-film layers, such as the magnetic recording layer could be damaged without observable damage to the protective top surface carbon overcoat. The exact location and extent of damage to the magnetic recording layer depends on the scratch load, size of scratch tip, and the friction at the interface. Such permanent deformation in magnetic recording layer could lead to demagnetization, which has been reported in the literature.

Stress Induced Permanent Magnetic Signal Degradation of Perpendicular Magnetic Recording System

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Sung-Chang Lee ◽  
Soo-Youl Hong ◽  
Na-Young Kim ◽  
Joerg Ferber ◽  
Xiadong Che ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Hard Disk Drives ◽  
Magnetic Layer ◽  
Mechanical Damage ◽  
Hard Disk ◽  
Disk Drive ◽  
Magnetic Signal ◽  
Perpendicular Magnetic Recording ◽  
Signal Degradation ◽  
The Media

Model scratches of the size found in hard disk drives are produced under controlled conditions at a series of applied loads on both longitudinal magnetic recording (LMR) media and perpendicular magnetic recording (PMR) media using a diamond tip. The scratches are created at low speed, eliminating thermal considerations from the interpretation of the media response. Nanoindentations are produced as well. The scratches and indentations are characterized by atomic force microscope (AFM), magnetic force microscope (MFM), and also by the same magnetic reader and writer used in an integrated hard disk drive (HDD). A comparison of the response of PMR and LMR media shows the PMR media to have larger scratches and greater magnetic signal degradation than LMR media for a given scratch load. The extent of magnetic damage, as measured by MFM, is greater than the extent of surface mechanical damage, as measured by AFM. Analysis of scratches using the HDD reveals that the magnetic damage is irreversible and permanent damage in magnetic layer, which is confirmed by cross section transmission electron microscope image. The experiments reveal the mechanism for magnetic scratch erasure in the absence of thermal effects. This understanding is expected to lead to improved designs for mechanical scratch robustness of next-generation PMR media.

scholarly journals A study of perpendicular magnetic recording media using polarized SANS

2014 ◽  
Vol 70 (a1) ◽  
pp. C148-C148
Author(s):  
Stephen Lister ◽  
Vikash Venkataramana ◽  
Thomas Thomson ◽  
Joachim Kohlbrecher ◽  
Ken Takano ◽  
...  
Keyword(s):  
Thin Film ◽  
Data Storage ◽  
Magnetic Recording ◽  
Magnetic Moments ◽  
Magnetic Films ◽  
Oxide Shell ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Recording Layer ◽  
Perpendicular Magnetic Recording

The study of thin film magnetic systems that are structured on the nanoscale is an area of intense interest. Small-angle neutron scattering is an extremely powerful probe of nanomagnetism in the bulk, but in thin-film systems the experiments are challenging due both to the small scattering volume available and also to scattering from other sources such as the substrate and sample environment. We have demonstrated that such experiments are however possible in magnetic films as thin as 10 nm. A good example to illustrate this is the case of perpendicular magnetic recording media. These materials are found in all modern magnetic hard drives, the data storage technology that continues to be of tremendous commercial and technological importance. These media are advanced functional multilayered materials, containing an active recording layer of only around 10 nm in thickness. This recording layer is compositionally segregated into 8 nm-sized grains of a magnetic CoCrPt alloy separated by a thin oxide shell, typically SiO2. These media have their magnetic moments oriented perpendicular to the plane of the film. Determining the local magnetic structure and reversal behavior is key to understanding the performance of perpendicular media in recording devices. Polarised SANS has proved to be a very effective tool to measure these materials at a sub-10nm length scales. The signal of interest must however also be distinguished from the scattering from other layers in the structure, some of which are also magnetic. We will present a summary of some recent results on recording media, including measurements of the grain-sized dependent switching with and without the presence of an exchange spring. We will also briefly mention experiments that demonstrate the viability of extending this approach to measurement for lithographically defined structures similar to those for application in bit-patterned media, including 2d artificial spin-ice and structurally glassy arrays.

Towards Terabit/in2 Magnetic Storage Media

2008 ◽  
Vol 1106 ◽  
Author(s):  
Dimitris Niarchos ◽  
E. Manios ◽  
I. Panagiotopoulos
Keyword(s):  
Magnetic Recording ◽  
Signal To Noise Ratio ◽  
Hard Disk ◽  
Modern Society ◽  
Disk Drive ◽  
Computer Applications ◽  
Consumer Electronics ◽  
Magnetic Storage ◽  
Navigation Systems ◽  
Data Intensive

AbstractIn modern society there is an almost insatiable demand for ever increasing storage capacities in computers and consumer electronics. Magnetic recording is the dominant storage technology and the hard disk, due to its versatility, is becoming a pervasive device in various applications. The soaring demand arises from data-intensive computer applications, including graphics, animation, multimedia and desktop publishing, to which can be added a growing market for non-PC consumer devices such as set-top boxes, cameras, mobile phones, laser printers and satellite navigation systems. In response to this demand the hard disk drive manufacturers have come forward with spectacular increase in storage capacities and densities over the last decade. It is currently projected that the evolution of conventional perpendicular recording storage density in the hard disk industry will reach a limit of 500 Gbit/in2, while further progress will require major breakthroughs and alternative technologies. In this presentation we will review the state-of-the-art in magnetic recording media and we will discuss the future approaches to reach densities in excess of 1 Tbit/in2 densities along the three axes : a) self-assembled coercive nanoparticles, b) exchange spring media and percolated media, and c) bit-patterned media (nanoscale patterning). This entails resolving several conflicting requirements with regard to signal to noise ratio (SNR) , writability and thermal stability of these new promising systems.

ULTRA-THIN FILM DEPOSITION AND CHARACTERISATION OF 10nm AMORPHOUS CARBON LAYERS FOR APPLICATIONS IN MAGNETIC STORAGE DEVICES

2000 ◽  
Vol 14 (02n03) ◽  
pp. 167-180 ◽  
Author(s):  
J. Mc Lauglin ◽  
P. Maguire ◽  
A. Ogwu ◽  
R. Lamberton ◽  
Jun Fu Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Carbon ◽  
Magnetic Recording ◽  
Film Growth ◽  
Barrier Properties ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Magnetic Storage ◽  
Deposition Techniques ◽  
Ultra Thin Film

The paper will present an overview of our latest results using various ultra-thin film amorphous carbon deposition techniques, and focus on first to grow studies, nano-characterisation of the electrical, mechanical and barrier properties associated with films grown on various substrate types applied to the magnetic recording industry. Although some of the characterisation is carried out on 10nm coatings, the nanomechanical measurements are performed on samples with thickness values between 30nm to 200nm. This overview of our work deals with PECVD deposition techniques and examines ultra-thin film growth on Si and Al 2 O 3: TiC substrates. Some results are presented on the functional benefits of doping a-C:H films with Silicon and Nitrogen. All the work is related to the ability to produce effective 3nm to 10nm overcoat layers for new magnetic recording applications.

scholarly journals Materials for Magnetic Data Storage: The Ongoing Quest for Superior Magnetic Materials

MRS Bulletin ◽  
2006 ◽  
Vol 31 (5) ◽  
pp. 374-378 ◽  
Author(s):  
Hans Coufal ◽  
Lisa Dhar ◽  
C. Denis Mee
Keyword(s):  
Magnetic Materials ◽  
Data Storage ◽  
Magnetic Recording ◽  
Magnetic Tape ◽  
High Performance ◽  
Materials Science ◽  
Disk Drive ◽  
Magnetic Data Storage ◽  
Magnetic Data ◽  
Magnetic Storage

AbstractFrom its inception until today, and for the foreseeable future, magnetic data storage on disks and tape has provided constantly increased storage density.This has required not only constant innovation, but also major breakthroughs in magnetic materials, both for the media and the read head. Today's disk and tape drives take advantage of novel nanoengineered composite magnetic materials and quantum mechanical processes.In this issue of MRS Bulletin, we present a number of review articles by some of the leaders in this rapidly moving field that highlight the key materials science accomplishments that have enabled the tremendous progress in hard disk drive and magnetic tape technologies.Individual articles describe the materials involved in state-of-the-art magnetic recording, advanced media for perpendicular magnetic recording, the materials challenges of achieving high performance in flexible media such as magnetic tape, the materials issues of read heads, and future avenues for magnetic storage beyond magnetic recording, such as nanowires and spintronics.

High-resolution scanning electron microscopy of thin-film magnetic media of magnetic recording disk

1992 ◽  
Vol 50 (2) ◽  
pp. 1334-1335
Author(s):  
K. Ogura ◽  
H. Nishioka ◽  
N. Ikeo ◽  
T. Kanazawa ◽  
J. Teshima
Keyword(s):  
Thin Film ◽  
Fine Structure ◽  
High Resolution ◽  
Magnetic Recording ◽  
High Performance ◽  
Magnetic Hysteresis ◽  
Grain Structure ◽  
Magnetic Media ◽  
Cross Sectional ◽  
Resolution Observation

Structural appraisal of thin film magnetic media is very important because their magnetic characters such as magnetic hysteresis and recording behaviors are drastically altered by the grain structure of the film. However, in general, the surface of thin film magnetic media of magnetic recording disk which is process completed is protected by several-nm thick sputtered carbon. Therefore, high-resolution observation of a cross-sectional plane of a disk is strongly required to see the fine structure of the thin film magnetic media. Additionally, observation of the top protection film is also very important in this field.Recently, several different process-completed magnetic disks were examined with a UHR-SEM, the JEOL JSM 890, which consisted of a field emission gun and a high-performance immerse lens. The disks were cut into approximately 10-mm squares, the bottom of these pieces were carved into more than half of the total thickness of the disks, and they were bent. There were many cracks on the bent disks. When these disks were observed with the UHR-SEM, it was very difficult to observe the fine structure of thin film magnetic media which appeared on the cracks, because of a very heavy contamination on the observing area.

Trends in digital magnetic recording; the application of thin-film heads for tape recording

1998 ◽  
Vol 51 (1) ◽  
pp. 5-19 ◽  
Author(s):  
S.B. Luitjens ◽  
W. Folkerts ◽  
H.W. Van Kesteren ◽  
J.J.M. Ruigrok
Keyword(s):  
Thin Film ◽  
Magnetic Recording ◽  
Tape Recording
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