Anisotropy field distributions in magnetic recording particles

1990 ◽  
Vol 67 (9) ◽  
pp. 5158-5160 ◽  
Author(s):  
F. T. Parker ◽  
A. E. Berkowitz
Keyword(s):  
Magnetic Recording ◽  
Anisotropy Field ◽  
Field Distributions

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.

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