X-Ray and Neutron Diffraction Studies of Modified
Bi0.8A0.2FeO3 (A = La, Ba) Multiferroics
Manisha Rangi*1, Ashish Agarwal1, Sujata Sanghi1, Ripandeep Singh2, A. Das2
1
Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar-125001 (Haryana)
India;
2
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085 India
*Corresponding Author’s Email: mrangi100@gmail.com, Tel.:+91-9812684543
Abstract
The effect of di- and trivalent substitution on the
crystal and magnetic structure in BiFeO3 has been investigated
using X-ray and neutron diffraction techniques. Rietveld
analyses of the XRD and ND patterns of single phase
Bi0.8A0.2FeO3 (A= La, Ba) multiferroics revealed that the
prepared ceramics exhibit rhombohedral structure with space
group R3c.
Keywords: Modified BiFeO3; X-ray Diffraction; Neutron
Diffraction; Rietveld refinement;
Introduction
The materials in which ferroelectricity and
ferromagnetism exist simultaneously are very much
useful in the magneto electric and magneto optical
devices like spintronic devices, sensors, transducers [1].
BiFeO3 (BFO) belongs to this class and its functionality
at room temperature makes it more important than other
multiferroics. BFO is antiferromagnetic at room
temperature. So, to improve magnetic properties,
substitution of ions is done [2]. Therefore, in the present
work modified BiFeO3 (BFO) ceramics have been
prepared by solid state reaction method and
modification is done by La, Ba at Bi site.
300K is shown in Fig.1. The lattice parameters of the
Bi0.8La0.2FeO3 and Bi0.8Ba0.2FeO3 multiferroics obtained
from refinement of ND data are a=5.5603Å,
c=13.7836Å,
V=369.05Å3
and
a=5.6337Å,
c=13.6730Å, V=375.82 Å3 respectively. As ionic radii
of substituent ion increased, the lattice parameter and
vol. increased.
Table 1. Refined atomic positions of Bi0.8La0.2FeO3
Atom
x
y
z
__________________________________________
Bi/La
0.0
0.0
0.2238
Fe
0.0
0.0
0.0000
O
0.8864
0.6467
0.4348
_________________________________________
Experimental
High purity Bi2O3, La2O3, SrCO3 BaCO3, Fe2O3
(purity ˃ 99% Sigma-Aldrich) reagents were taken in
stoichiometric ratio, mixed properly and grounded in an
agate mortar to obtain a homogenous mixture. These
mixtures were calcined at 5000C for 7h and sintered at
8500C for 5h to obtain a single phase perovskite. XRD
patterns were collected by using Rigaku Miniflex-II
diffractometer with Cu Kα radiation in the 2θ range from
200 to 800 with the scanning rate of 20 min-1 at room
temperature. Neutron diffraction patterns were recorded
on the PD2 powder diffractometer (ʎ = 1.244Å) in
Dhruva reactor in Bhabha Atomic Research Centre,
Mumbai between temperature 6K to 300K.
Fig 1. Reitveld refinement of neutron diffraction data of
Bi0.8La0.2FeO3 sample at 300K
Acknowledgement
The authors are thankful to DST, New Delhi
(FIST) for providing XRD and BARC for Neutron
Diffraction facilities. One of the author (M. Rangi) is
thankful to UGC, Delhi for providing JRF (17-06/2012
(i) EU-V).
Results
References
XRD pattern indicates that all the synthesized
samples are single phase perovskite. Rietveld
refinement of XRD and ND data is performed by
GSAS-EXPGUI and FULLPROF program respectively.
The refinement of all the samples is performed using the
same space group, i.e. R3c and all the peaks are
reproduced in the refinement. Reitveld refinement of
neutron diffraction data of La substituted BFO sample at
[1] W. Eerenstein, N. D. Mathur, and J. F. Scott.,’’
Multiferroic and Magnetoelectric Materials’’, Nature,
442 (2006) 05023.
[2] I. Sosnowska, R. Przeniosło, P. Fisher, and V. A.
Murov.,’’Neutron diffraction studies of the crystal and
magnetic structure of BiFeO3 and Bi0.93La0.07FeO3’’,
Journal of Magnetism and Magnetic Materials, 160
(1996) 384.