Cation distribution in ferrimagnetic Ni1-xZnxFe2O4
:57Fe Mossbauer and Raman spectroscopy study
Sanjay Kumar Upadhaya and V.Raghavendra Reddy*
UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore – 452 001, India
*
e-mail:vrreddycsr73@gmail.com; vrreddy@csr.res.in
Introduction
Polycrystalline Ni1-xZnxFe2O4 (x= 0 to 1 @ 0.2) samples
are prepared by conventional solid-state reaction
starting from the oxide precursors. The prepared
A
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(3
(2
2g
T
T
)
(1
X=0.2
)
)
nfo
.
1g
X=0
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It is well know that the magnetic properties of ferrites
are governed by the distribution of cations at tetrahedral
and octahedral sites [1]. Many experimental methods
viz., x-ray diffraction, neutron diffraction, 57Fe
Mossbauer etc., are used to measure the cation
distribution in ferrites [1,2]. It may be noted that out of
all the techniques, 57Fe Mossbauer under the application
of external magnetic fields is extensively used to study
the ferrites [2]. One can get the information regarding
the Fe distribution, spin canting etc., using Mossbauer
measurements. However, in systems such as Ni1xZnxFe2O4, where one is having more than one magnetic
cations, Mossbauer measurements cannot give the
distribution of all the cations as the Mossbauer is
sensitive to Fe only. In such cases, it is required to use
other complementary methods to corroborate the results
that are obtained from Mossbauer measurements.
Recently, Silva et al., have used Raman measurements
in addition to the Mossbauer measurements to find out
the degree of inversion in Zn1-xMgxFe2O4 [3]. In the
present work, series of Ni1-xZnxFe2O4 samples are
prepared and cation distribution is estimated using
Raman spectroscopy and 57Fe Mossbauer measurements
under the application of external magnetic fields.
The prepared samples are phase pure (from the XRD)
and the magnetization values are found to vary as a
function of Ni concentration (not shown) matching with
the literature. Figure 1 show the 57Fe Mossbauer data of
all the samples measured at 5K and with the application
of 5Tesla magnetic field parallel to the gamma rays and
Raman data measured at room temperature. Both the
data are used to find the distribution of cations in the
system. The obtained distribution is cross checked with
magnetization data as obtained from VSM data.
E
Introduction
Results
2g
Keywords: Ferrites, Mossbauer spectroscopy and Raman
spectroscopy
samples are studied using x-ray diffraction for phase
purity. Magnetic measurements are carried out using
PPMS-VSM. Raman measurements are carried out
using micro Raman spectrometer.
High field
Mossbauer measurements are carried out using standard
PC based spectrometer.
T
The present study reports the preparation and study of
ferromagnetic Ni1-xZnxFe2O4 (x= 0 to 1 @ 0.2) using x-ray
diffraction,
magnetization,
Mossbauer
and
Raman
spectroscopy techniques. The cation distribution is estimated
using low temperature 57Fe Mossbauer and Raman
spectroscopy measurements and the results are correlated with
magnetization measurements.
ni8
Intensity (arb.units)
Abstract
X=0.4
ni6
ni4
ni2
X=0.6
zfo
X=0.8
200
300
400
500
600
700
-1
Raman Shift (cm )
X=1.0
-10
-5
0
5
10
Velocity (mm/s)
Fig. 1: 57Fe Mossbauer, Raman data of Ni1-xZnxFe2O4
Acknowledgments
Authors thank Dr.Mukul Gupta, Dr.V.Sathe and Dr.
A.Banerjee for XRD, Raman and magnetization data.
References
[1] L.K.Leung et al., Phys. Rev. B., 8 (1973) 29
[2] N. Lakshmi et al., Phys. Rev. B., 80 (2009) 174425
[3] S.W.de Silva et al., J. Nanopart Res (2012) 14, 798