Read Back Signals in Magnetic Recording - Research Group Fidler

µ 0 Hsig [T]
0.030
0.025
0.020
0.015
0.010
0.005
Analytical Calculations
0.000
-200 -100 0 100 200
x [nm]
Figure 3.4: The effective signal field as function of the relative position of the read head in
respect to a perfect transition (Js = 0.5 T).
3.2.4 Signal of Written Bits
The maximum read back signal is achieved for perfect transitions. In practice written bits do
not have perfect transitions. Figure 3.5 shows the results of two recording simulations with a
head velocity of 10 m/s and 20 m/s.
Figure 3.5: These two figures show the x-component of the magnetization (Js = 0.5 T) of
the data layer after a write process with head velocity 10 m/s (left) and 20 m/s (right). Red
color represents magnetization in positive x-direction and blue color magnetization in
negative x-direction. The scale is in µm, thus the bit length is approximately 40 nm. The
data layer thickness is 12 nm.
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