
96-11Magnetic and Optical Recording
When an MR head is used for reproducing, the MRE is usually sandwiched between two magnetic
shields to increase its spatial resolution to medium signals, as shown in Figure 96.8. Since the MR head
is u
x-sensitive,
th
e
in
cident
u
x
ϕ
i
, on the bottom surface of the MRE, should be derived as a function
of the distance (x) between the center of MRE and the center of the transition [7,8]:
φ
µ δ
π
i
r
( )
( ) ( )/ ( )/
x
wM a d
g
f
x g t
a d
f
x t
a d
=
+ + +
+
−
+
+
2 2 2
0
+
− −
+
−
−
+
f
x g t
a d
f
x t
a d
( )/ ( )/2 2
(9
6
.11
)
where
g
i
s
t
he
d
istance
b
etween
t
he
M
RE
a
nd
t
he
s
hield
t
i
s
t
he
M
RE
t
hickness
f ( ) ln
β