Anantharaman, M R; Saravanan, S; Joseph, Mathai C; Venkitachalam, S; Prabhakaran, P V(Wiley Periodicals, July 23, 2003)
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Abstract:
Electrically conductive organic and metalloorganic
polymers are of great interest and they have applications
in electronic, optical, photonic, photoelectric, electrochemical,
and dielectric devices. Tetrameric cobalt phthalocyanine
was prepared by conventional chemical method.
The dielectric permittivity of the tetrameric cobalt phthalocyanine
sample was evaluated from the observed capacitance
values in the frequency range 100 KHz to 5 MHz and
in the temperature range of 300 to 383°K. It is found that the
system obeys the Maxwell Wagner relaxation of space
charge phenomenon. Further, from the permittivity studies
AC conductivity was evaluated. The values of AC conductivity
and DC conductivity were compared. Activation energy
was calculated. To understand the conduction mechanism
Mott’s variable range hopping model was applied to
the system. The T 1/4 behavior of the DC conductivity along
with the values of Mott’s Temperature (T0), density of states
at the Fermi energy N (EF), and range of hopping R and
hopping energy W indicate that the transport of charge
carriers are by three-dimensional variable range hopping
Description:
Journal of Applied Polymer Science, Vol. 91, 2529–2535 (2004)
Anantharaman, M R; Sagar, S(Springer, January 31, 2011)
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Abstract:
Materials belonging to the family of manganites are technologically important since they exhibit colossal
magneto resistance. A proper understanding of the transport properties is very vital in tailoring the properties. A
heavy rare earth doped manganite like Gd0·7Sr0·3MnO3 is purported to be exhibiting unusual properties because
of smaller ionic radius of Gd. Gd0·7Sr0·3MnO3 is prepared by a wet solid state reaction method. The conduction
mechanism in such a compound has been elucidated by subjecting the material to low temperature d.c. conductivity
measurement. It has been found that the low band width material follows a variable range hopping (VRH) model
followed by a small polaron hopping (SPH) model. The results are presented here
Description:
Bull. Mater. Sci., Vol. 35, No. 1, February 2012, pp. 41–45.