Theoretical limit on digital magnetic recording density

1963 ◽  
Vol 51 (2) ◽  
pp. 394-395 ◽  
Author(s):  
D.W. Chapman
Keyword(s):  
Magnetic Recording ◽  
Theoretical Limit ◽  
Recording Density

Coupled Granular/Continuous Media – Results and Challenges

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2661-2668
Author(s):  
Horia Gavrila ◽  
Doina Elena Gavrila
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Magnetic Recording ◽  
Granular Media ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Theoretical Limit ◽  
Perpendicular Recording ◽  
Perpendicular Magnetic Recording ◽  
Longitudinal Recording

ABSTRACTWhile the most promising longitudinal recording systems cannot surpass the theoretical limit of about 200 Gb/in2 for areal recording density and the demand for higher densities is permanently increasing, the perpendicular magnetic recording constitutes the realistic issue to the longitudinal one. The perpendicular magnetic recording offers significant advantages, the most important being stronger write and read fields, and therefore the use of media of higher anisotropy, smaller grain size, higher signal-to-noise ratio, and a better thermal stability. Unfortunately, the perpendicular recording has to cope some important physical and technological difficulties. To overcome them, many ingenious solutions were proposed. In this paper the coupled granular/continuous (CGC) media, a subtle association of the continuous and, respectively, granular media, are analysed from the viewpoint of their magnetic and recording properties. The challenges and possible improvements of CGC media are discussed.

Patterned Magnetic Recording Media – Issues and Challenges

2016 ◽  
Vol 1817 ◽  
Author(s):  
Horia Gavrila ◽  
Doina Elena Gavrila
Keyword(s):  
Thermal Stability ◽  
New Media ◽  
Magnetic Recording ◽  
Large Fraction ◽  
Hard Disk Drives ◽  
Anisotropy Field ◽  
Anisotropy Constant ◽  
Nano Particles ◽  
Recording Density ◽  
Geometry Parameter

ABSTRACTThe conventional magnetic recording approached the physical frontiers of the recording density. The magnetic recording must face the famous trilemma: In order to increase the recording density, smaller grain volumes are needed, but in order to ensure the thermal stability of recorded information, the anisotropy constant should be increased accordingly; what results is an increased anisotropy field, which requires higher writing fields. Such fields are unavailable with the maximum saturation magnetization obtainable with the magnetic materials of the current heads. In order to overcome these problems, new media structures have been proposed. The most promising is the bit-patterned magnetic media (BPM), intensively studied over the last years with the aim of obtaining obtain an ultra-high recording density of hard-disk drives. A BPM comprises monodisperse high-anisotropy nano-particles in a self-organized patterning. They have a higher thermal stability, a lower noise and a higher signal resolution, which leads to a higher recording density and a better SNR. They eliminate the transition noise and, due to the large fraction of the bit volume occupied by the magnetic dots, improve thermal stability. Nevertheless, some important issues such as long-range patterning, control of the surface roughness, signal readout, etc., remain critical problems to solve. Another challenge is the fact that recording on BPM is sensitive to the material and geometry parameter fluctuations that may lead to additional constraints and require tight synchronization of the write-field misregistration time and bit positions. A possible route to higher recording densities is to use a multilevel recording, where more than two states are stored per dot.

Thermally assisted magnetic recording with bit-patterned media to achieve areal recording density beyond 5Tb/in2

2012 ◽  
Vol 324 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Fumiko Akagi ◽  
Masaki Mukoh ◽  
Masafumi Mochizuki ◽  
Junko Ushiyama ◽  
Takuya Matsumoto ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Recording Density ◽  
Thermally Assisted Magnetic Recording

Quantum limit of magnetic recording density

2001 ◽  
Vol 79 (10) ◽  
pp. 1501-1503 ◽  
Author(s):  
G. A. Held ◽  
G. Grinstein
Keyword(s):  
Magnetic Recording ◽  
Quantum Limit ◽  
Recording Density

Recent advances and opportunities in magnetic recording materials

1993 ◽  
Vol 51 ◽  
pp. 1010-1011
Author(s):  
Mark H. Kryder
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Grain Boundaries ◽  
Magnetic Materials ◽  
Magnetic Recording ◽  
Magnetocrystalline Anisotropy ◽  
High Coercivity ◽  
Recording Density ◽  
The Future ◽  
Materials Used

Recording densities in magnetic recording products manufactured today are of the order of 200 Mbit/in. However, it is projected that densities as high as 10 Gbit/in will be achieved in the future. To achieve this, substantial improvements in the thin film magnetic materials used for magnetic heads and media are required.To support higher recording density in thin film media, it is necessary to increase the coercivity, while simultaneously achieving small grain size and small intergranular coupling. To achieve high coercivity, materials with large magnetocrystalline anisotropy are used, while to achieve small, well-isolated grains, special materials are used and deposited under conditions which promote either heavily voided grain boundaries or the segregation of non-magnetic species to the grain boundaries. It is also thought to be important to control the orientation of the crystallites so that a preferred axis of magnetization lies parallel to the direction of recording.

Improvement of Recording Density of Amorphous TbFeCo Magnetic Recording Layer on FeC Soft Magnetic Back Layer

2002 ◽  
Vol 41 (Part 2, No. 6B) ◽  
pp. L691-L693 ◽  
Author(s):  
Koji Matsumoto ◽  
Hiroyasu Kawano ◽  
Takeshi Morikawa ◽  
Keiji Shono
Keyword(s):  
Magnetic Recording ◽  
Soft Magnetic ◽  
Recording Layer ◽  
Recording Density
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