ISSN: 1693-6930
TELKOMNIKA Vol. 14, No. 3A, September 2016 : 306 – 312
307 measure light transmission, one need to adjust adjustable polarizer light L
1
and L
2
until equal light intensity values is reached. The
＝
beam intensity ratio η I
1
I
2
is defined as light transmittance, namely relative transmittance of light. Without magnetic field, the relative light
transmittance is 1, with magnetic field, the relative light transmittance can tell the influence of field-deduced light transmission for the ferrofluids. At room temperature, the effect of field-
deduced light transmission for samples ZnFe
2
O
4
ferrofluids, FeOOH ferrofluids and FeOOH- ZnFe
2
O
4
binary ferrofluids are measured, the corresponding mechanism are analyzed theoretically.
Figure 1. The sketch map of experimental device
3. Results 3.1. The TEM and VSM Measure of ZnFe
2
O
4
and α-FeOOH Nanoparticles
Figure Figure 2a and Figure 2b are the TEM and VSM test chart of ZnFe
2
O
4
and α-
FeOOH nanoparticles. From the figure both are ball-shaped. Size distribution of the nanoparticles, produced by chemical co-precipitation technology, is lognormal distributed.
x
d d
ln
] ln
2 ln
ln exp[
ln 2
1
2 2
g g
g
x x
1
Where
x
the diameter of the nanoparticles,
g
x is the geometric average particle size,
g
is the geometric standard deviation of size distribution. So 4.22nm and 8.16nm are the geometric average particle sizes of ZnFe
2
O
4
nanoparticles and α-FeOOH nanoparticles, 0.26 is
the geometric deviations. As ZnFe
2
O
4
is weak magnetic, its magnetization curve is linear, the initial susceptibility
T k
mM dH
dM
B s
H i
3
[5], of which
2 1
3
2
T k
d m
B i
d
as particles diameter [6]. Thus, effective susceptibility of ZnFe
2
O
4
,
i
is
2
10 49
. 1
, coupling constant between particles,
T k
d m
B 3
2
2
, is calculated as
2
10 73
. 3
. α-FeOOH nanoparticles is weak magnetic,
effective susceptibility,
i
, is
3
10 80
. 9
, coupling constant between particles, , is
3
10 45
. 2
.
3.2. Field-Deduced Effect of Light Transmission for Sample ZnFe
2
O
4
Ferrofluids
At the experiment, sample ZnFe
2
O
4
ferrofluids is placed in the experiment device. It’s 30s after transmitted light becomes stable, respectively, that 700Gs, 900Gs, 1100Gs and
1300Gs of magnetic field is coupled. It’s observed that the intensity of transmitted light unchanged over time. Even when the magnetic field is removed from the 1200s, its light
transmittance remains the same over time. As shown in Figure 3.
TELKOMNIKA ISSN: 1693-6930
The Field-Induced Effect of Light Transmission for FeOOH-ZnFe2O4 … Anrong Wang 308
a the ZnFe
2
O
4
particles b
b the α-FeOOH particles
Figure 2. Magnetization curve and TEM picture of the particles
Figure 3. Field-deduced effect of light transmission for sample ZnFe
2
O
4
ferrofluids when the magnetic field is 1300Gs
ISSN: 1693-6930
TELKOMNIKA Vol. 14, No. 3A, September 2016 : 306 – 312
309
3.3. Field-Deduced Effect of Light Transmission for Sample FeOOH Ferrofluids
Sample FeOOH Ferrofluids is placed in the experiment device. It’s 30s after transmitted light becomes stable, respectively, 700Gs, 900Gs, 1100Gs and 1300Gs of magnetic field is
coupled. The intensity of transmitted light is observed over time. Even when the magnetic field is removed from the 1200s, its light transmittance remains the same over time, as shown in
Figure 4.
a when the magnetic field is 700Gs b when the magnetic field is 900Gs
c when the magnetic field is 1100Gs d when the magnetic field is 1300Gs
Figure 4. Field-deduced effect of light transmission for sample FeOOH ferrofluid From the experiment, the moment the magnetic field is coupled to the sample FeOOH
ferrofluids, the rates of light transmission increases greatly before it remain stable. When the magnetic field is removed, the light transmission returns to 1 quickly.
3.4. Field-Deduced Effect of Light Transmission for Sample FeOOH-ZnFe
2
O
4
Ferrofluids
Sample FeOOH-ZnFe
2
O
4
ferrofluids is placed in the experiment device. It’s 30s after transmitted light becomes stable, respectively, 700Gs, 900Gs, 1100Gs and 1300Gs of magnetic
field is coupled. The magnetic field is removed after the 1200s. The intensity of transmitted light is observed over time, as shown in Figure 5.
From the experiment, the moment the magnetic field is coupled to the sample ferrofluids, the rates of light transmission increases greatly. The stronger the field, the more
intensified the light transmission. When the magnetic field is removed, the light transmission drops and returns to 1 or so.
TELKOMNIKA ISSN: 1693-6930
The Field-Induced Effect of Light Transmission for FeOOH-ZnFe2O4 … Anrong Wang 310
a when the magnetic field is 700Gs b when the magnetic field is 900Gs
c when the magnetic field is 1100Gs d when the magnetic field is 1300Gs
Figure 5. Field-deduced effect of light transmission for sample FeOOH-ZnFe
2
O
4
Ferrofluids
4. Discussions 4.1. Analysis of Field-Deduced Effect of Light Transmission for Sample ZnFe
