Magnetic Materials and Device Physics

Understanding the physics behind various nanoscopic, mesoscopic and bulk magnetic materials and realization of their usage in practical devices such spin-electronics, opto-electronics, semiconducting devices, nano-electronics, ultrasonics and bioscience is one of the aims of my present research. Fundamentally, novel properties emerge in magnetic elements as the material dimensions become comparable to or smaller than certain characteristic length scales, such as spin diffusion length, carrier mean free path, magnetic exchange length, domain wall width, etc. When the size of magnetic material reduces, the magnetic properties of them would alter based on their dimensions. Such a strong dependence on the geometry allows one then to tailor the magnetization configuration by appropriately engineering the geometry. In addition, under extreme conditions such as very low temperatures, high magnetic fields and high pressures, one can realize quantum effects. Under these extreme and normal conditions understanding the structural, magnetic, electrical and optical properties are of great interest.

Recent

Talk entitled "Magneto-transport through magnetostrictive nanocontacts" @ IIT Madras (Invited) (2019)
Mr. U. M. Kannan received Dr. K. V. Rao Scientific research award (2019)
Mr. U. M. Kannan received Travel grant to attend ICMAT 2019 conference @ Singapore (2019)
Mr. Dwipak Prasad Sahu received Travel grant to attend ICMAT 2019 conference @ Singapore (2019)
Magneto-transport in magnetostrictive nanocontacts (invited) at IIT Mandi during discussion meeting on recent advances in magnetism (2019)
Talk on "Quantum transport through atomic junctions" at IISC, Bengaluru (2019)
Molecular magnets under pulsed high magnetic fields (Invited) at BARC , Visakhapatnam during the workshop on "Discussion meeting on pulsed high magnetic fields" (2019)
Magnetotransport in molecular junctions (Invited) at BITS Hyderabad during the workshop on "Characterization and modelling of magnetic materials" 13th - 14th July 2018
Current and future memory technologies - a resistive random access memory (Invited) at Center for Nanotechnology, University of Hyderabad (2018)
Magnetostrictive Nanocontacts (Invited) in Functional Magnetic Materials workshop at University of Hyderabad (2018)
Memory devices and TiO2 based RRAM - (Invited) talk at VBIT, Ghatkeswar (On the eve of Science day as Chief guest) (2018)
Current and future memory technologies based on resistance switching (Invited) talk at NCDFMA - 2017, KL University Vijayawada (2017)
Remote control of resistive random access memory (Invited) talk at ICAFM 2017, IIIT Basara,
Conductance switching and tunneling of electrons in magnetostriction based nanocontacts (Invited) International conference on nanotechnology, IIT Roorkee (2017)
Extension lecture at Medak govt. degree college (Invited) (2017)
Spin-Phonon Coupling in HoCr1-xFexO3 (x = 0 and 0.5) compounds (Accepted J. Raman Spectroscopy)
Remote control of resistive switching in TiO2 based resistive random access memory device (accepted Nature Scientific reports)
Magnetic and magnetocaloric properties of HoCr0.75Fe0.25O3 compound (accepted, AIP Advances (2017)
Structural and spectroscopic studies on HoCr1-xFexO3 (x= 0 and 0.5) Compounds (DAESSPS 2017) (Accepted)
Magnetic And Optical Effects In TiO2 Based Dye Sensitized Solar Cells (DAESSPS 2017) (Accepted)
Preparation of Folic Acid conjugated Hematite Nanoparticles using High Energy Ball Milling for Biomedical Applications (DAESSPS 2017) (Accepted)
Magnetic and exchange bias properties of YCo thin films and IrMn/YCo bilayers, accepted Journal of magnetism and magnetic materials (2017)
Inverse and enhanced magnetocaloric properties of HoCrO3, accepted, Journal of alloys and compounds (2017)
Magnetic and Hyperfine interactions in HoFe1-xCrxO3 compounds, accepted, Journal of Magnetism and Magnetic Materials (2017)
Spin - orbit coupling and Lorentz force enhanced efficiency of TiO2 based dye sensitized solar cells accepted, Physica Status Solidi A (2016)
Influence of negative field cooling on exchange bias properties of potassium split GNRs" accepted, Journal of Materials science and engineering A (2016)
Magnetostrictive Fe73Ga27 nanocontacts for low-field conductance switching, Appl. Phys. Lett. 108, 242408 (2016)
Magnetocaloric effect and nature of magnetic transition in low dimensional DyCu2, accepted "J. Alloys and compounds" (2016)
Tuning optical properties of graphene oxide under compressive strain using wet ball milling method accepted, "Graphene" (2016)
Enhanced spin - reorientation temperature and origin of magnetocapacitance in HoFeO3 (In press J. of Magnetism and Magnetic Materials) (2016)
Invited talk by JS entitled "Remote control of magnetostriction based nanocontacts" at ICMAGMA (2015)
Oral talk by JS entitled "Detection of ultrafast heat pulses from molecular magnet - Mn12 - Acetate" at ICMAGMA (2015)
Poster presentation "Positive EB in potassium split GNRs" by Mr. Venkat Narayana at ICMAGMA (2015)
Poster presentation "Tuning the SR temperature and magnetocapacitance in HoFe1-xCrxO3" by Mr. Ganesh Kotnana at ICMAGMA (2015)
Remote control of nanocontacts" paper published in "Nature Scientific Reports 5, 13621 (2015)
Band gap tuning and orbital mediated electron - phonon coupling .. J. Appl. Phys. 118, 124101 (2015)
Spin reversal in Fe8... paper published in New Journal of Physics 17, 073006 (2015)

Selected publications

17. Demagnetization field driven charge transport in a TiO2 based dye sensitized solar cell

Solar Energy, Volume 187, 15 July 2019, Pages 281-289 (with U. M. Kannan)

16. Remote control of resistive switching in TiO2 based resistive random access memory device

Scientific Reports 7, 17224 (2017) (With Dwipak Sahu)

15. Spin - orbit coupling and Lorentz force enhanced efficiency of TiO2 based dye sensitized solar cells

Physica status solidi A, 1600691 (2017) (With U. M. Kannan)

14. Magnetostrictive Fe73Ga27 nanocontacts for low-field conductance switching

Appl. Phys. Lett. 108, 242408 (2016) (With U. M. Kannan)

13. Band gap tuning and orbital mediated electron - phonon coupling in HoFe1-xCrxO3

J. Appl. Phys. 118, 124101 (2015) (With Ganesh Kotnana)

12. Remote control of magnetostriction-based nanocontacts at room temperature

S. Narayana Jammalamadaka, S. Kuntz, Oliver Berg, W. Kittler, U. M. Kannan, J. Arout Chelvane, and Christoph Surgers

Scientific Reports 5, 13621 (2015)

11. Spin reversal in Fe8 under fast pulsed magnetic fields

S. Narayana Jammalamadaka, S Vélez, J Vanacken, V V Moshchalkov, L Chibotaru, J Tejada and F Macià

New Journal of Physics 17, 073006 (2015)

10. Resistive switching in ultra-thin La0.7Sr0.3MnO3/SrRuO3 superlattices

S. Narayana Jammalamadaka, J. Vanacken and V. V. Moshchalkov

Appl. Phys. Lett., 105, 033505 (2014)

09. Dynamic response of exchange bias in graphene nanoribbons

S. Narayana Jammalamdaka, SRINIVASA SINGAMANENI RAO , Johan Vanacken, Victor V. Moshchalkov ,

Wei Lu , James M. Tour

Appl. Phys. Lett 101, 142402 (2012)

08. Ferromagnetism in Graphene Nanoribbons: Split versus Oxidative Unzipped Ribbons

S. S. Rao*, S. Narayana Jammalamadaka*, A. Stesmans, and V. V. Moshchalkov ,

J. van Tol , D. V. Kosynkin, A. Higginbotham-Duque, and J. M. Tour

Nano Lett. 12, 1210 (2012) (*equal contribution)

07. Exchange bias and training effects in antiferromagnetically coupled La0.7Sr0.3MnO3/SrRuO3

superlattices

S. Narayana Jammalamadaka, J. Vanacken and V. V. Moshchalkov

Europhysics Letters 98 17002 (2012)

06. S. Narayana Jammalamadaka, G. Markandeyulu and Krishnan Balasubramaniam

Magnetostriction and anisotropy compensation in TbxDy0.9-xNd0.1Fe1.93 [0.2 ? x ? 0.4]

Appl. Phys. Lett. 97, 242502 (2010)

05. S. Narayana Jammalamadaka, Niharika Mohapatra, Karthik K. Iyer and E. V. Sampathkumaran

Enhancement of positive magnetoresistance following a magnetic-field-induced ferromagnetic transition in the

intermetallic compoundTb5Si3

Phys. Rev. B Rapid communications 79, 060403 (2009)

04. Sitikantha D. Das, S. Narayana Jammalamadaka and E. V. Sampathkumaran

Magnetic ordering in the fine particles of some bulk Pauli-paramgnets

Phys. Rev. B 80, 024401 (2009)

03. S. Narayana Jammalamadaka, E. V. Sampathkumaran, V. Satya Narayana Murthy and G. Markandeyulu

Room temperature soft ferromagnetism in the nanocrystalline form of YCo2 - a well-known bulk Pauli paramagnet

Appl. Phys. Lett. 92, 192506 (2008)

02. S.Narayana Jammalamadaka, G.Markandeyulu, Elankumarn Kannan and Krishnan Balasubramaniam

Development of 100 kHz high power ultrasonic magnetostrictive transducer for Non-Destructive Testing.

Appl. Phys. Lett. 92, 044102 (2008)

01. Niharika Mohapatra, S. Narayana Jammalamadaka, Sitikantha D. Das and E.V. Sampathkumaran

Magnetic anomalies in Nd6Co1.67Si3: Surprising first order transitions in the low-temperature isothermal magnetization (2008)

Phys. Rev. B 78, 054442 (2008)

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