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Giant Dielectric Permittivity and Weak Ferromagnetic
Properties in (1-x)LaFeO3-(x)BaTiO3 (x=0.00, 0.05)
Ceramic
T. Sreenivasu1, K.Chandra Mouli1, K.Prabahar3Y.Ramesh Babu4 and Patri Tirupathi2*
1
Department of Engineering Physics, Andhra University College of Engineering, Visakhapatam-530003, India.
2
Department of Physics, Rajiv Gandhi Universities of Knowledge Technologies, RK Valley-516329, India.
3
Advanced Magnetic group, Defense Metallurgical Research Laboratory, Hyderabad - 500058, India.
4
Department of Physics, G.Pulla Reddy College of Engineering, Kurnoo- 518007,India.
*
Corresponding author’s e-mail: [email protected], Tel.: +91-8332872902; Fax: +040 – 23001830
Abstract
The multiferroic (1-x)LaFeO3-xBaTiO3 (x=0.0,0.05) ceramics
were synthesized by solid-state reaction method. Rietveld
refined XRD clearly shows orthorhombic phase with Pbnm
space group. The giant dielectric permittivities were noted. In
addition, dielectric loss relaxation was reported which can be
ascribed to polaranic conduction. Enhanced properties with
weak ferromagnetic nature and positive MD effect also noted
for x=0.05.
Keywords: Multiferroic, Magneto-Dielectric, Ceramic.
Introduction
Multiferroic ceramics are characterized by
simultaneous presence of two or more ferroic order
parameters and coupled via magnetoelectric interaction
[1,2]. Recently, these materials has received
considerable attention in novel device applications due
to extra degree of freedom between order parameters
i.e., magnetic polarizations using electric field or vice
versa [1]. Amongst the few room temperature
multiferroics, LaFeO3 is most prominence and its solid
solutions are also widely studied ME systems. LaFeO3,
at room temperature, has orthorhombic unit cell with
Pbnm space group. It containing only trivalent iron and
exhibiting a high value of the Neel temperature (T N -740
K) and ferroelectric transition at 830°C [2-4].
Various strategies are being investigated to
improve enhance the ME performance of LaFeO3 at
room temperature. Amongst these, synthesis of solid
solution with strong ferroelectric materials is also most
acceptable. In this paper, we report the synthesis (1x)LaFeO3-(x)BaTiO3 (x=0.00, 0.05) solid solution,
along with enhanced dielectric and magneto-dielectric
properties.
Experimental
The samples are prepared using standard
ceramic synthesis route. These powders are calcined at
1200°C for 6h and calcinations procedure were repeated
for twice to get pure phase of the system. The phase
analysis was carried out by X-ray diffraction. Dielectric
properties were measured with impedance analyzer HP
4192A with temperature intervals of 100K-350K and
500 Hz-1M Hz frequency range. Magnetic and
magneto-dielectric studies also studied using SQUIDVSM magnetometer with field of 6T.
Result and Discussion
The Rietveld refinement of XRD for these
ceramics show the orthorhombic unit cell with Pbnm
space group. The micrograph of ceramic show high
density, with average grain size was 2-5 μm range.
Temperature dependent dielectric permittivity shows
giant permittivity value for LaFeO3 and small amount of
BaTiO3 doping, shows significant enhancing in giant
permittivity values.
Along with dielectric loss
relaxation, shows the frequency dispersion which can be
polaronic conduction. The estimated activation energies
Fig .1 M-H loops of (1-x)LaFeO3-xBaTiO3
ceramics (a) x=0.00; (b) x=0.05. Variation of
coercivity with temperature of the corresponding
ceramics (c) x=0.00; (d) x=0.05.
are well agreed with polaronic activation energies. In
addition to, temperature dependent M-H loops also
shows large magnetic moment with weak ferromagnetic
nature. Furthermore, Positive MD effect at room
temperature was noted. The details of enhanced
magnetic and magneto dielectric properties with suitable
explanation will be given in complete paper.
References
[1] D. Khomskii, Physics 2, (2009) 20.
[2] S. Acharya, J. Mondal, S. Ghosh, S. K. Roy, and P.
K. Chakrabarti, Materials Letters 64, (2010) 415.
[3] C. Chen, K. B. Xu, Y. M. Cui, and C. C. Wang,
Materials Letters 89, (2012) 153
[4] A. Singh and R. Chatterjee, Appl. Phys. Lett. 93,
(2008) 182908.
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