Biomedical Engineering Reference
In-Depth Information
BFO-00_MT_0.1T
FC & ZFC (Field 999.844 Oe)
BFO-10_MT_0.1T
FC & ZFC (Field 1000.068 Oe)
0.0105
0.0088
ZFC
FC
ZFC
FC
0.0100
0.0086
0.0095
0.0084
0.0082
0.0090
0.0080
0.0085
0.0078
0.0080
0.0076
0.0075
0.0074
0.0070
0.0072
0
50
100
150
200
250
300
350
0
50
100 150 200 250 300 350 400
Temp(K)
Temp (K)
(
a
)
(
b
)
Figure 13.28
M~T curve of Bi
1-x
La
x
FeO
3
(x=0.0 and x=0.1) measured at 0.1T.
When the same compound is substituted with 10% La and the measure-
ment was done under the identical conditions of temperature and i eld (that
is from 10 K to 325 K at magnetic i eld of 0.1T) under the same FC and
ZFC conditions, the M~T curve (Figure 13.28b) gets reversed from concave
nature in the pure compound to parabolic nature. h us La substitution not
only enhances the insulation behavior of the parent compound, but also
improves the magnetic behavior from antiferro- towards ferromagnetic.
With a further increase of La concentration from x=0.1 to x=0.2, the
M~T curve (Figure 13.29a) shows broadness in parabolic nature under
both FC and ZFC conditions. h e separation between FC and ZFC are
more of an indication that the lattice distortion is more with the enhance-
ment of La-concentration, which is responsible for the enhancement of
exchange and superexchange interaction with enhanced spin canting,
hence increased spin moment.
With a further increase of concentration from x=0.2 to x=0.3, the M~T
curve (Figure 13.29b) shows a convex behavior like a ferromagnet. h ere
is a slight dif erence between FC and ZFC curves at lower temperature but
conciding at higher temperature. Further increase of concentration from
x=0.3 to 0.4 indicates that the M~T curves (Figure 13.30a) measured under
FC and ZFC conditions coincide with each other and look like a typical
ferromagnetic curve.
Similar behavior has been observed in the case of x=0.5 in M~T curve
(Figure 13.30b) under the same FC and ZFC conditions. Here both the FC
and ZFC curves coincide with each other with typical convex nature of the
ferromagnetic material. From the M~T studies of all these samples it can
be observed that with the increase of La concentration on the Bi site, the
