Study of magnetization in Ga-substituted cobalt ferrite
using magnetic Compton scattering
H. S. Mund_11, A. Sharma_21, J. Sahariya_32, S. Tiwari_43, M. Itou_54, Y. Sakurai_64, B. L.
Ahuja_71
1
Department of Physics, M. L. Sukhadia University, Udaipur 313001, India
2
Department of Physics, Manipal University, Jaipur-303007, India
3
Department of Physics, Govt. Women Engineering College, Ajmer 305002, India
4
Experimental Research Division, Japan Synchrotron Radiation Research Institute, SPring-8, Mikazuki, Hyogo 6795198, Japan
*
Corresponding author’s e-mail:hmoond@gmail.com, Tel.: +91-9468905220
Abstract
We present the magnetic Compton profiles (MCPs) of Ga doped
CoFe2O4 using synchrotron radiations. The major contribution in
the formation of total spin moment mainly arises from Co while
itinerant electrons show negative polarization. Total spin
moment increases remarkably on increasing doping of nonmagnetic Ga in the base cobalt ferrite.
Keywords: Doped ferrites, Spin-orbit coupling, X-ray scattering,
Ferromagnetic materials, Synchrotron radiations.
Introduction
Magnetic Compton scattering (MCS), which
employs circularly polarized synchrotron radiation, is a
well established technique to probe the spinuncompensated electron density distribution in materials
with spontaneous magnetization.8 To examine the effect
of partial substitution of Ga at Fe site on the total and site
specific spin moments of CFO, we present the
temperature dependent MCPs of Ga doped CoFe2O4.
Table I: Temperature dependent magnetic moments
derived from the line shape analysis of MCPs of
CoGaxFe2-xO4 (x=0.2, 0.3) ferrites
Doping
of Ga
0.2
0.3
T (K)
8
300
8
300
Magnetic moment in μB/f.u.
Co
Fe
Diffuse Total SQUID
2.68 1.43
-0.23 3.88 4.54
3.01 0.04
-0.55 3.00 3.64
2.77 1.56
-0.25 4.08 4.83
1.68 0.97
-0.05 2.60 3.23
Experiment
We have used high energy inelastic scattering
beamline at SPring8, Japan for the measurement of
MCPs.11 The energy of incident x-rays and degree of
circular polarization were kept as 182.65 keV and 0. 55,
respectively.
Result and Discussion
The MCP based total spin moment of Ga doped
CFO (at 8, 200 and 300 K) along with individual spin
moments of their constituents are collated in Table I. It is
interesting to note that increase in doping of Ga ions from
x=0.2 to 0.3 increases the spin moment. Co has the largest
contribution in the formation of total spin moment for
both the doped ferrites.
To deduce the orbital moment, we have
subtracted our MCP data from the magnetization data.
The origin of orbital moment in such system may be
explained on the basis of crystal field splitting and spin
orbit interactions.
Figure 1: Magnetic Compton profiles (MCPs) of
CoGa0.2Fe1.8O4 (Inset Ga 0.3) at 8 K temperature.
Acknowledgment
We are thankful to JASRI for magnetic Compton
scattering measurement at SPring8, Japan for providing
beamtime for experiment (No. 2011B1069).
[1] M.J. Cooper, P.E. Mijnarends, N. Shiotani, N. Sakai,
and A. Bansil, X-ray Compton Scattering, Oxford
University Press, Oxford, 2004.
[2] Y. Kakutani, Y. Kubo, A. Koizumi, N. Sakai, B.L.
Ahuja, and B.K. Sharma, “Magnetic Compton Profiles of
Fcc-Ni, Fcc-Fe50Ni50 and Hcp-Co” J. Phys. Soc. Jpn. 72,
3 (2003), pp. 599-606