K Saravana Kumar

Hello! Welcome to saravanakumar.org website.

Hi! I am Dr K. Saravana Kumar and currently working as Assistant Professor at Sri S.R.N.M. College Sattur.

As a Materials Scientist, I am interested in Magnetic Materials, Multiferroic Materials, Magneto-dielectric Materials, Dielectric Materials, Perovskite and Double Perovskite Materials. I always feel delighted to be inspired from the Nature for technological developments, and convey the same to my students while I teach as well as when I consider my future research prospects.

Initially, I obtained my Ph.D. degree from Unversity of Madras under the guidance of Prof. C. Venkateswaran (Department of Nuclear Physics) in the field of BiFeO3 Multiferroic Materials. I have the experience of Teaching and Research at SRM Institute of Science and Technology, Ramapuram for about 5 years. Currently, I enjoy teaching Undergraduate Physics and helping them understand the way physics helps in their everday life at Sri S.R.N.M. College, Sattur.

I have been conducting an on-demand Online Hands-on Training Programme on Rietveld Analysis of Powder Diffraction Pattern for people from various walks of research (Postgraduate Students, Research Scholars, Assistant Professors). I am deeply of the opinion that understanding the basic properties of materials thoroughly only will lead to technological applications.

I always love to share information, both scientific and general, which I find interesting. This website is all about interesting information.

selected publications

Appl. Phys. A
A novel double perovskite oxide Sm2CoFeO6 phosphor for orange LEDs structural, magnetic and luminescence properties

M. Dhilip, J. Stella Punitha, R. Rameshkumar, and 7 more authors

Applied Physics A Mar 2022

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Double perovskite Sm2CoFeO6 (SCFO) compound has been synthesized by the conventional solid-state reaction route for the first time. The Rietveld refinement has been carried out using the X-ray diffraction data; it confirms the single-phase formation of orthorhombic structure with the Pnma space group. UV-DRS results show that SCFO was observed in semiconducting behavior. Spin–phonon coupling of SCFO was observed from Raman spectroscopy investigation. The Raman analysis and group theory confirms that the IR and Raman active modes of SCFO. The amount of Sm, Co, Fe and O elements in the SCFO compound was examined by energy-dispersive spectroscopy (EDS) with the assistance of field emission scanning electron microscopy (FE-SEM) analysis. The photoluminescence excitation and emission spectra of SCFO were examined. The results show that the phosphor is excited in the region from 320 to 500 nm, and it emits orange at 607 nm, due to the resultant of 4G5/26H7/2 transitions. The SCFO compound exhibited ferromagnetic behavior, which is confirmed by VSM analysis. The obtained results demonstrated that SCFO double perovskite is extensive for application of spintronic devices and LED’s.
@article{Dhilip2022, author = {Dhilip, M. and Punitha, J. Stella and Rameshkumar, R. and Rameshkumar, S. and Karuppasamy, P. and Pandian, Muthu Senthil and Ramasamy, P. and Kumar, K. Saravana and Anbarasu, V. and Elangovan, K.}, title = {A novel double perovskite oxide Sm2CoFeO6 phosphor for orange LEDs structural, magnetic and luminescence properties}, journal = {Applied Physics A}, year = {2022}, month = mar, day = {20}, volume = {128}, number = {4}, pages = {324}, issn = {1432-0630}, doi = {10.1007/s00339-022-05446-8}, url = {https://doi.org/10.1007/s00339-022-05446-8}, }
JMSME
Synthesis and characterization of phase-stabilized Gd2FeMnO6 double-Perovskite compound

J. Stella Punitha, A. Nataraj, V. Anbarasu, and 2 more authors

Journal of Materials Science Materials in Electronics Mar 2021

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In the recent past, a series of double-perovskite compounds with the molecular formula of A2BB’O6 have gained keen interest among other inorganic compounds. It is due to the fact that the exhibition of large variety of physical properties pertaining to the elements accommodated at A, B and B’ sites. In connection to the preparation of Gd2FeMnO6, a novel single-phased double perovskite compound has been carried out using conventional solid-state reaction route. Rietveld refinement of powder XRD patterns reveals that the compound crystallizes in orthorhombic crystal structure with a space group Pbnm. X-ray photoelectron spectroscopy analysis confirms the presence of Mn and Fe ions in +3 oxidation state. The field emission scanning electron micrograph reveals the granular growth morphology, having grains with irregular shape with the average grain size of about 5–10 µm. Room-temperature magnetization measurement reveals the dominant antiferromagnetic behaviour with weak ferromagnetic interactions. Deconvoluted Raman spectra using Lorentzian function confirm the first and second orders of Raman modes of the prepared compound. The activation energy value of Ea = 0.16 eV obtained from the Arrhenius plot indicates the dielectric stability of the material. The photoluminescence study shows the excitation by the light from ultraviolet region (350 to 450 nm), exhibiting blue (355 nm) to 8S7/2 → 6P3/2 transition, which may provide new applications in the field of modern electronics.
@article{Punitha2021, author = {Punitha, J. Stella and Nataraj, A. and Anbarasu, V. and Dhilip, M. and Kumar, K. Saravana}, doi = {10.1007/s10854-021-05682-3}, isbn = {1085402105682}, issn = {1573482X}, issue = {8}, journal = {Journal of Materials Science Materials in Electronics}, pages = {10266-10276}, publisher = {Springer US}, title = {Synthesis and characterization of phase-stabilized Gd2FeMnO6 double-Perovskite compound}, volume = {32}, url = {https://doi.org/10.1007/s10854-021-05682-3}, year = {2021}, }
Dal. Trans.
Role of oxygen vacancy and Fe-O-Fe bond angle in compositional, magnetic, and dielectric relaxation on Eu-substituted BiFeO3 nanoparticles

A. Tamilselvan, S. Balakumar, M. Sakar, and 3 more authors

Dalton Transactions Mar 2014

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The influence of oxygen vacancies on the dielectric relaxation behavior of pure and Eu-substituted BiFeO3 nanoparticles synthesized by a sol-gel technique has been studied using impedance spectroscopy in the temperature range of 90 °C to 180 °C. The electric relaxation time and activation energy of the oxygen vacancies can be calculated from the Arrhenius equation, and found to be 1.26 eV and 1.76 eV for pure and Eu-substituted BiFeO 3, respectively. Substitution induces structural disorder and changes in the Fe-O-Fe bond angle, leading to alteration of the magnetic properties, observed from magnetic studies and evaluated using Rietveld refinement of the XRD patterns. X-ray photoelectron spectroscopy (XPS) confirms the shifting of the binding energy of the Bi 4f orbital, establishing Eu substitution at the Bi site. Calculation of the area under the Fe2+/Fe3+ (2p) and O (1s) XPS spectra gives approximate values of the oxygen vacancies. © 2014 the Partner Organisations.
@article{Tamilselvan2014, author = {Tamilselvan, A. and Balakumar, S. and Sakar, M. and Nayek, Chiranjib and Murugavel, P. and Kumar, K. Saravana}, doi = {10.1039/c3dt52260a}, issn = {14779234}, issue = {15}, journal = {Dalton Transactions}, pages = {5731-5738}, title = {Role of oxygen vacancy and Fe-O-Fe bond angle in compositional, magnetic, and dielectric relaxation on Eu-substituted BiFeO3 nanoparticles}, volume = {43}, year = {2014}, }
J. Phy. D Ap. Phy.
Effect of Fe substitution on the magnetic properties of BiMn 2O5

K. Saravana Kumar, and C. Venkateswaran

Journal of Physics D Applied Physics Mar 2011

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Powders of BiFeMnO5, by the substitution of Fe ions at Mn 3+ sites of parent BiMn2O5 system, were synthesized by a two-step process initial high-energy ball milling of oxides in zirconia vials and then sintering of the as-milled powders. BiFeMnO5 has orthorhombic structure (Pbam) as that of the parent system, determined from X-ray diffraction. Above 850 °C it melts and transforms to a multi-phase system. Smaller particle size is observed from scanning electron microscopy in comparison with parent BiMn2O5. Thermo-magnetization studies indicate a Neel transition around 40 K. Isothermal magnetization measurements reveal paramagnetic nature at room temperature and a weak ferromagnetic property below the transition temperature. As an effect of Fe substitution in BiMn2O5, a significant increase in coercivity (Hc) and decrease in remanent magnetization (M r) are observed below transition temperature which is discussed based on the dynamics of exchange interaction. © 2011 IOP Publishing Ltd.
@article{Kumar2011a, author = {Kumar, K. Saravana and Venkateswaran, C.}, doi = {10.1088/0022-3727/44/32/325001}, issn = {00223727}, issue = {32}, journal = {Journal of Physics D Applied Physics}, title = {Effect of Fe substitution on the magnetic properties of BiMn 2O5}, volume = {44}, year = {2011}, }
J. Phy. D Ap. Phy.
Mechanical milling assisted synthesis of Ba-Mn co-substituted BiFeO 3 ceramics and their properties

K. Saravana Kumar, C. Venkateswaran, D. Kannan, and 2 more authors

Journal of Physics D Applied Physics Mar 2012

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Samples of composition Bi 1-xBa xFe 1-xMn xO 3 (x=0, 0.1, 0.2) were synthesized by initial mixing of precursors by high-energy ball milling and subsequent sintering of the milled powders. The co-substitution of Ba-Mn controls the formation of impurity phases, as evident from x-ray diffraction analysis. Evidence of Fe in mixed oxidation states of +3 and +2 and Mn in +3 state is found from x-ray photoelectron spectroscopy. Electron microscopy exhibits a decrease in grain size due to inhibition in grain growth by Ba-Mn co-substitution. The magnetization value at 20kOe increases as the percentage of substitution increases. The x=0.2 sample exhibits a comparable and stable resistivity curve in the experimental temperature range and has a higher value of remanent polarization (P r) when compared with the x=0 sample. © 2012 IOP Publishing Ltd.
@article{SaravanaKumar2012, author = {Kumar, K. Saravana and Venkateswaran, C. and Kannan, D. and Tiwari, Brajesh and Rao, M. S. Ramachandra}, doi = {10.1088/0022-3727/45/41/415302}, issn = {00223727}, issue = {41}, journal = {Journal of Physics D Applied Physics}, title = {Mechanical milling assisted synthesis of Ba-Mn co-substituted BiFeO 3 ceramics and their properties}, volume = {45}, year = {2012}, }
JMMM
Effect of Tb-Mn substitution on the magnetic and electrical properties of BiFeO3 ceramics

K. Saravana Kumar, P. Aswini, and C. Venkateswaran

Journal of Magnetism and Magnetic Materials Mar 2014

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Tb-Mn co-substituted BiFeO3 of stoichiometry Bi 1-xTbxFe1-xMnxO3 (x=0, 0.10, 0.15, 0.20) has been synthesized by a solid-state reaction method. Inferences from X-ray photoelectron spectroscopy indicate the presence of Fe in mixed oxidation states i.e., Fe3+ and Fe2+. But in the Tb-Mn substituted samples, Fe is predominantly in +3 oxidation state and Mn is found to be in +3 state. There is a decrease in cell volume due to Tb 3+ substitution as Mn3+ ions have similar ionic radii as that of Fe3+. The grains of substituted samples have regular dimensions with agglomeration when compared to irregular shaped grains of BiFeO3. No major characteristic transitions are found in substituted samples as observed from the thermal measurements, but BiFeO3 shows a ferroelectric-paraelectric transition at 820 °C. A weak magnetic ordering is observed from the magnetization measurements at room temperature with the increase in substitution percentage. Impedance spectroscopy studies show the impact of Tb-Mn substitution on the conductivity of BiFeO3. The ferroelectric loop and leakage current studies with an applied electric field on samples also supplement the results obtained from impedance measurements. © 2014 Elsevier B.V.
@article{SaravanaKumar2014, author = {Kumar, K. Saravana and Aswini, P. and Venkateswaran, C.}, doi = {10.1016/j.jmmm.2014.04.008}, issn = {03048853}, journal = {Journal of Magnetism and Magnetic Materials}, keywords = {Impedance spectroscopy,Magnetic study,X-ray photoelectron spectroscopy}, pages = {60-67}, publisher = {Elsevier}, title = {Effect of Tb-Mn substitution on the magnetic and electrical properties of BiFeO3 ceramics}, volume = {364}, url = {http://dx.doi.org/10.1016/j.jmmm.2014.04.008}, year = {2014}, }
Vacuum
Conventional synthesis and characterization of cubically ordered La2FeMnO6 double perovskite compound

M. Dhilip, N. Aparna Devi, J. Stella Punitha, and 2 more authors

Vacuum Mar 2019

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The cubically ordered double perovskite compound, La2FeMnO6, has been synthesized using high temperature solid-state reaction method. Rietveld refinement of powder X-ray diffraction data indicates the formation of La2FeMnO6 compound, having cubic structure with space group Pm-3m. It is also inferred that the LaFeO3 perovskite structure accommodates the Mn3+ ions to stabilize the double perovskite La2FeMnO6 structure. The scanning electron micrograph reveals the uniform distribution of crystallites without any segregation. Energy dispersive spectra confirms the presence of La, Fe, Mn and O elements in the prepared compound. The existence of higher order Raman active vibrational modes confirms the phase purity of the prepared sample, where higher-order phonon modes may be related to the strong spin-lattice coupling arising from the interaction between the adjacent magnetic sublattices. The magnetic exchange interactions between transition metal ions influences the anti-ferromagnetic ordering (AFM) existing in the La2FeMnO6 compound. The magnetization measurement confirms the dominant exchange interactions between Fe3+ and Mn3+ ions in the material which provides a complex environment for the competition between ferri-magnetism (FIM) and AFM interactions. Hence, a phase pure double perovskite La2FeMnO6 compound prepared at high temperature is characterized for its structural, optical and magnetic properties.
@article{Dhilip2019, author = {Dhilip, M. and Devi, N. Aparna and Punitha, J. Stella and Anbarasu, V. and Kumar, K. Saravana}, doi = {10.1016/j.vacuum.2019.05.028}, issn = {0042207X}, issue = {March}, journal = {Vacuum}, keywords = {Double perovskites,Raman spectroscopy,Rietveld refinement,VSM}, pages = {16-20}, publisher = {Elsevier}, title = {Conventional synthesis and characterization of cubically ordered La2FeMnO6 double perovskite compound}, volume = {167}, url = {https://doi.org/10.1016/j.vacuum.2019.05.028}, year = {2019}, }
Mat. Chem. Phys.
Synthesis and characterization of nanostructured La-doped BaSnO3 for dye-sensitized solar cell application

Nandarapu Purushothamreddy, M. Kovendhan, Reshma K. Dileep, and 3 more authors

Materials Chemistry and Physics Mar 2020

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Nanostructured pure and lanthanum (La) doped (0.01%, 0.03% and 0.05%) perovskite BaSnO3 materials were synthesized by hydrothermal method and annealed at 1000 °C/2 h in air. Rietveld refinement of the XRD data indicated single-phase nature of the samples with cubic crystallographic structure. The morphology of pure and La-doped BaSnO3 (La–BSO) studied using scanning electron microscopy indicated the formation of distinct rod-like structures. Upon doping with La, the BSO nanorods disintegrated and tend towards a mixed nanorods-nanoparticle like morphology as confirmed from the TEM measurements. The XPS data confirmed La to be in 3+ oxidation state. The 0.03% La–BSO was found to have a higher value of band-gap. A maximum power conversion efficiency of 1.23% with a higher short circuit current density of 2.57 mA/cm2 was obtained for the DSSC fabricated using 0.03% La–BSO nanostructured material as a photoanode.
@article{Purushothamreddy2020, author = {Purushothamreddy, Nandarapu and Kovendhan, M. and Dileep, Reshma K. and Veerappan, Ganapathy and Kumar, K. Saravana and Joseph, D. Paul}, doi = {10.1016/j.matchemphys.2020.123137}, issn = {02540584}, issue = {May}, journal = {Materials Chemistry and Physics}, keywords = {Dye-sensitized solar cell (DSSC),La doped BaSnO3,Nanostructure,Perovskite}, pages = {123137}, publisher = {Elsevier B.V.}, title = {Synthesis and characterization of nanostructured La-doped BaSnO3 for dye-sensitized solar cell application}, volume = {250}, url = {https://doi.org/10.1016/j.matchemphys.2020.123137}, year = {2020}, }
Phys. B Con. Mat.
A simple experimental setup for magneto-dielectric measurements

P. Manimuthu, N. Praveen Shanker, K. Saravana Kumar, and 1 more author

Physica B Condensed Matter Mar 2014

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The increasing demand for the multiferroic materials calls for the need of an experimental setup that will facilitate magneto-dielectric coupling measurements. A connector setup designed makes it possible to measure and analyze the dielectric properties of the material under the influence of a magnetic field. The salient feature of this setup is in its incorporation with the already existing experimental facilities. © 2014 Elsevier B.V.
@article{Manimuthu2014, author = {Manimuthu, P. and Shanker, N. Praveen and Kumar, K. Saravana and Venkateswaran, C.}, doi = {10.1016/j.physb.2014.03.051}, issn = {09214526}, journal = {Physica B Condensed Matter}, keywords = {Connector setup,Impedance analyzer,Magneto-dielectric,Multiferroic,Vibrating sample magnetometer}, pages = {354-355}, publisher = {Elsevier}, title = {A simple experimental setup for magneto-dielectric measurements}, volume = {448}, url = {http://dx.doi.org/10.1016/j.physb.2014.03.051}, year = {2014}, }
AIP Conf. Proc.
Synthesis and study of Bi0.9Tb0.1Fe 0.9Mn0.1O3 ceramics

K. Saravana Kumar, and C. Venkateswaran

AIP Conference Proceedings Mar 2012

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The (Tb, Mn) co-substituted BiFeO3 samples were synthesized by the combined high-energy ball milling and sintering process. XRD study shows the formation of stoichiometric phase of rhombohedral (R3c) structure with minor impurity peaks. Particle size distribution with irregular morphology is observed from scanning electron microscopy. Room temperature magnetization measurement shows a hysteresis like behaviour without saturation, which is due to the suppression of spiral spin structure by co-substitution. © 2012 American Institute of Physics.
@article{Kumar2012, author = {Kumar, K. Saravana and Venkateswaran, C.}, doi = {10.1063/1.4710403}, isbn = {9780735410442}, issn = {0094243X}, issue = {1}, journal = {AIP Conference Proceedings}, keywords = {BiFeO3,Electron Microscopy,High-Energy Ball Milling,Magnetic Material,Multiferroics}, pages = {1125-1126}, title = {Synthesis and study of Bi0.9Tb0.1Fe 0.9Mn0.1O3 ceramics}, volume = {1447}, year = {2012}, }
IOP Conf. Ser.
Study on the properties of Fe-substituted NdMn2O5

K. Saravana Kumar, and C. Venkateswaran

IOP Conference Series Materials Science and Engineering Mar 2015

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The oxide, NdFeMnO5, has been synthesized using a two-step synthesis process. First the precursor oxides are high-energy ball milled and the as-milled powders are then sintered to obtain the NdFeMnO5 phase. X-ray diffraction confirms phase formation and the calculated pattern is obtained by the substitution of Mn3+ sites by Fe3+ sites. Agglomeration of small sized grains is observed from the scanning electron microscopy images. Room temperature magnetization measurement shows a paramagnetic behaviour. A ferrimagnetic ordering is observed to be established below ∼110 K from the thermo-magnetization measurements.
@article{Kumar2015a, author = {Kumar, K. Saravana and Venkateswaran, C.}, doi = {10.1088/1757-899X/73/1/012031}, issn = {1757899X}, issue = {1}, journal = {IOP Conference Series Materials Science and Engineering}, pages = {2-6}, title = {Study on the properties of Fe-substituted NdMn2O5}, volume = {73}, year = {2015}, }
J. Appl. Phy.
Mn doping instigated multiferroicity and magneto-dielectric coupling in KNbO3

M. Manikandan, K. Saravana Kumar, and C. Venkateswaran

Journal of Applied Physics Mar 2015

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KNb1-xMnxO3 (0 ≤ x ≤ 0.07) samples were synthesized by a two-step process, ball milling of the precursors and then sintering subsequently. Mn doping at Nb site induces a weak ferromagnetism at room temperature and it has been explained with the help of bound magnetic polaron model. Magnetization values at 15 kOe initially increase followed by a decrease with increase in the Mn concentration. Two phase transitions - orthorhombic to tetragonal and tetragonal to cubic, above room temperature were analyzed from the differential scanning calorimetry and temperature dependent dielectric studies. It elucidates the effect of Mn concentration on phase transition temperatures. All the samples exhibit a peak behaviour in the dielectric constant Vs temperature plot at phase transition temperatures. The samples also exhibit leaky ferroelectric loops at room temperature. PUND measurement reveals the true ferroelectric polarization of the samples. The probable origin of magneto-dielectric effect is discussed based on the dielectric study in the presence of variable magnetic field at a frequency of 1 kHz.
@article{Manikandan2015b, author = {Manikandan, M. and Kumar, K. Saravana and Venkateswaran, C.}, doi = {10.1063/1.4938118}, issn = {10897550}, issue = {23}, journal = {Journal of Applied Physics}, pages = {0-6}, title = {Mn doping instigated multiferroicity and magneto-dielectric coupling in KNbO3}, volume = {118}, year = {2015}, }