Photon Factory Activity Report 2022 #40 (2023)
BL-16A/2021G501

Electronic and Magnetic Properties of Fe1.3Mn0.7O3 Nanoparticles using
Soft X-Ray Magnetic Circular Dichroism
R. DAWN1, M. ZZAMAN1, R. PAL2, V K. VERMA3, K. KUMAR4, K. AMEMIYA5 andV. R. SINGH1*
1

Department of Physics, Central University of South Bihar, Gaya 824236.
2
Department of Chemistry, Madanapalle Institute of Technology & Science,Madanapalle, 517325, India.
3
Department of Physics, VIT-AP University, Amaravati 522237 A.P. India.
4
Department of Physics, Ranchi University, Ranchi 834008, India.
5
Photon Factory, IMSS, High Energy Accelerator Research Organization, Tsukuba, Ibaraki
305-0801, Japan.

1. INTRODUCTION:
The
nanocrystalline
perovskite ferrites have attracted interest among due
to its adverse range in the technological field ofsensors, catalysts, pigments, magnetic storage,spintronic devices, magnetic resonance imaging,and so on [1, 2]. The perovskite structures are foundto be more flexible for their structural phasetransition properties particularly at lowertemperature. Nanostructured mangneous ferrite
materials
among
those
perovskitesareacknowledgeable for their remarkable electrical andmagnetic properties. Iron-Manganese oxide orcommercially known Bixbyite (FeMnO3) based
mixed systems have an essential application as
superparamagnetic materials, oxidation catalysis
and thermistors [1-3]. The Fe-Mn-O nanocrystalline
systems are also interesting due to the fact that Mn
is an element generally found in iron ore. The
incorporation of Mn in steel greatly influences its
metallurgical properties [3]. Fe-Mn based oxidesystems are also well in demand for their catalytic
properties [3]. The electronic as well as the magnetic
properties of the cubic FeMnO3 are related to thedistribution of cations from one lattice site to theother influencing the hopping of electrons which
nurtures the conductivity of the material. Therefore,
multivalence state becomes possible that plays amajor role in varying the magnetic and electronic
properties. In FeMnO3, hopping is between
Fe3+↔Fe2+ and Mn3+↔Mn4+ results in theoccurrences of oxygen vacancy and creation ofdefects. In the present case, we have prepared FeMn-O system in complex cationic configuration of
Fe1.3Mn0.7O3 through sol-gel combustion process tostudy its cationic distribution that enhances its
magnetic and eletronic variations. In FeMnO3, Feand Mn have distinct crystallographic sites, and ateach site, 50% of the occupant is either Fe or Mn. In

this very study, sample combination is resulting in aratio of 65:35 for Fe to Mn. Such a strong anti-site
disorder for both sites in FeMnO3 is expected tocome out with some interesting physical properties
which can also be further modified for technologicalimportance. According to previous temperaturedependent magnetism studies of FeMnO3 is found to
be antiferromagnetic at low temperature ~36K, inroom temperature it shows ferrimagnetism. Thus, it
motivated us to study the magnetic properties of
Fe1.3Mn0.7O3
nanoparticles bymeansofsynchrotron-based X-ray Absorption Spectroscopy(XAS) and X-ray Magnetic Circular Dichroism(XMCD). It is well known that XAS and XMCD are
one of the most sensitive techniques for detecting theinfluence of local structure on magnetic ions, andtemperature dependent magnetic phase transitions.
2. EXPERIMENT: Polycrystalline Fe1.3Mn0.7O3
powder was synthesized by a facile sol-gel
combustion method. The precursor solution wasprepared by taking stoichiometric quantities of ferricnitrate (Fe(NO3)2·9H2O) and manganese acetate
tetrahydrate((CH3COO)2Mn·4H2O).
These
ingredients were dissolved thoroughly in thedeionized water, and succinic acid was added
dropwise to the solution as a chelating agent. The
solution was stirred continuously to ensure
homogeneity at 70 °C heating until the gelformation. The obtained gel was dried at 120 °C for
12 hours. It was then calcined at 300 °C in the air for
4 hours to vapour-out the organic constituents andfinally the powder was sintered at 900 °C for 4hours. The crystallinity and phase formation of thesample is verified by X-ray Powder Diffraction.
To study further the element specific electronic andmagnetic properties, X-ray spectroscopy, scattering,Photon Factory Activity Report 2022 #40 (2023)
BL-16A/2021G501

Fig 1(a) Normalised XAS spectra and 1(b)Normalised XMCD spectra of Fe L-edge w.r.t.
applied magnetic-field ±1.0T. 1(c) XMCD/XAS
Intensity ratio w.r.t. applied magnetic-field 0T,±1.0T and ±2.0T @ Fe L-edge.
and imaging experiments were performed at thevariable-polarization soft x-ray beam-line BL-16Aof the Photon Factory (KEK, Japan). Experimental
geometry of soft x-ray absorption (XAS) and x-ray
magnetic circular dichroism (XMCD) experiments
are shown in Fig. 1 and 2. The sample was placed in
the vacuum chamber with a pressure of 10−9 Torr
equipped with a 5 T superconducting magnet. XASand XMCD signals were measured at 0T, ±1T and±2T with varying magnetic-fields (only the data ofFig 2(a) Normalised XAS spectra and 2(b)Normalised XMCD spectra of Mn L-edge w.r.t.
applied magnetic-field ±1.0T. 2(c) XMCD/XAS
Intensity ratio w.r.t. applied magnetic-field 0T,±1.0T and ±2.0T @ Mn L-edge.

±1T has been produced here) with right and left
circularly polarized (RCP and LCP) x-rays having
an energy resolution of 0.1 eV using the surfacesensitive total electron yield (TEY) method near Feand Mn L2,3 absorption edges with right and left
circularly polarized (RCP & LCP) x-rays.
RESULTS AND DISCUSSIONS: The XAS spectra
obtained with applied magnetic fields of +1.0 and 1.0 T are denoted by + and - which represent left
and right circularly polarized light, respectively as

Photon Factory Activity Report 2022 #40 (2023)
BL-16A/2021G501
shown in Fig 1. The XMCD spectrum was recordedby taking a difference between the XAS spectra withnegative and positive helicity of the circularpolarized light. In the Fe1.3Mn0.7O3 polycrystalline
sample, the Fe absorption spectra shows a multiplet
structure at the L3 and L2 edges. Well-resolved peaks
at the absorption maxima at E = 710.22 eV and708.85 eV exhibits a doublet structure at the L3 edge,whereas, maxima at E = 722.83 eV at L2 edge isclearly observable. This verifies that the finestructures of Fe 2p → 3d transition should result
from the localization of Fe 3d electrons with
Fe3+↔Fe2+ oxide formation. Since Fe 3þ can befurther oxidized to higher valence states, oxygenrich secondary phases can emerge. Fe 3d6 wasassumed as an initial state and Fe 3d3 was the finalconfiguration. The observed fine structure of theXAS spectrum of Fe also corresponds to the one
calculated from the multiplet effects [Fig. 1(a)].
XMCD signal measured in a magnetic field of B
=1.0 T as shown in Fig.1(b) for Fe-edges. Despitethat the magnitude of the XMCD measured at theL2,3 edges of Fe is clear that the signs of the dichroic
signals are the same. The XMCD signal at the Fe L2edge is notably suppressed, indicating magnetic
ordering due to fully occupied t2g level. TheXMCD/XAS intensity ratio w.r.t. the variablemagnetic field with ±0T, ±1.0T and ±2.0T are shownin Fig 1(c) for Fe-edges. This result is quite relatablewith the XMCD graphs. Fig 1(c) exhibits that theintensity ratio of XMCD/XAS is decreasing withincreasing magnetic-field. In a same manner, Mn
L2,3 edge shown in Fig 2(a). Mn absorption shows amultiplet structure at the L3 and L2 edges at E =641.81 eV and 653.17 eV doublet splitting is clearlyobservable. This verifies that the fine structures ofMn 2p → 3d transition should result from thelocalization of Mn 3d electrons with oxide formationof Mn3+. Mn 3d5 was assumed presence of Oxygen
K-edge is shown in Fig 2(a). XMCD measured at theL2,3 edges of Mn show dichroic signals at the same.
If anyone wants to calculate quantitative spin andorbital magnetic moment then using sum-rule [4-8]
it can be derived.

ACKNOWLEDGEMENTS: The experiment atthe Photon Factory was approved by the Program
Advisory Committee (Proposal Nos. 2021G501.
Authors acknowledges support from UGC-BSR
Start-up Research Grant F.30-395/2017(BSR).

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*Electronic Email: vijayraj@cusb.ac.in