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Papers by THIRUNAVUKKARASU G

Research paper thumbnail of ACCIDENT IDENTIFICAION AND THEFT AVOIDING SYSTEM USING EMBEDDED SYSTEM

Research paper thumbnail of Tomographic nanofabrication of ultrasharp three-dimensional nanostructures

Applied Physics Letters, 2008

We present the extension of electron tomography from a pure characterization technique into a thr... more We present the extension of electron tomography from a pure characterization technique into a three-dimensional nanofabrication technique using focused electron beams in the scanning transmission electron microscope. Two-dimensional surface patterning techniques are insufficient to achieve full three-dimensional nanosculpting, instead, multiple sample rotations under the beam are required. We demonstrate fabrication of ultrafine tips and hollow structures with applications in scanning probe microscopy, atom probe tomography, or in magnetoconductance of nanobridges. A sharpened tip radius of <3 nm is achieved, an order of magnitude finer than with standard methods.

Research paper thumbnail of A novel tripod-driven platform for in-situ positioning of samples and electrical probes in a TEM

Journal of Physics: Conference Series, 2010

... BD Medford1, BL Rogers1, D Laird1, N Berdunov1, AJ Lockwood2, T Gnanavel2, W Guan2, J Wang2, ... more ... BD Medford1, BL Rogers1, D Laird1, N Berdunov1, AJ Lockwood2, T Gnanavel2, W Guan2, J Wang2, G Möbus2, BJ Inkson2 and PH Beton1* 1 School of Physics &amp;amp;amp;amp; Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK 2Department of Engineering Materials ...

Research paper thumbnail of Nanoscale sculpting of ferromagnetic structures by electron beam ablation

Journal of Physics: Conference Series, 2010

Abstract. We report an electron beam (e-beam) fabrication method to produce sub-5 nm structures, ... more Abstract. We report an electron beam (e-beam) fabrication method to produce sub-5 nm structures, eg nanohole-arrays, nanojunctions and nanotips inside a TEM. The method is demonstrated using ferromagnetic nickel cross-sectional TEM specimens as well as electrochemically etched nickel tips. Different e-beam shapes and electron guns are compared, including point versus line focus and field-emission versus LaB6 guns. As an extension of this 2-D patterning of nanostructures, a 3-D nanofabrication technique has ...

Research paper thumbnail of Nanoporous structures from anodisation of non-planar aluminium surfaces

Journal of Physics: Conference Series, 2010

We report about a novel combination of two etching techniques for generating nanostructures, whic... more We report about a novel combination of two etching techniques for generating nanostructures, which individually are well established: (i) metal tip etching in NaOH, as e.g. used for STM or atom probe tip making, and (ii) anodic oxidation of aluminium for the generation of self-organised ordered pores. The non-planar geometry in both these etching processes allowed us to follow the

Research paper thumbnail of In-situ cobalt nanocrystal synthesis by intense electron beams in TEM

Journal of Physics: Conference Series, 2012

We report the synthesis of cobalt nanoparticles of a range of sizes from raw cobalt fluoride powd... more We report the synthesis of cobalt nanoparticles of a range of sizes from raw cobalt fluoride powder using high intensity focused electron beams and their characterisation in-situ in a TEM. A variety of beam intensities with different focussing level in a JEOL JEM 3010 TEM at an acceleration voltage of 300 kV is used. Depending on the beam intensity either a distribution of a large number of nanoparticles of 1-150 nm size or singular/a small number of fine metal particle(s) of ~150 nm up to micron size can be produced. Mechanisms of the nanoparticle formation are discussed. This simple, organic precursor free, non-hazardous and oxide-free fabrication method offers great potential for basic research, as it allows the fabrication of fresh particles "on demand" in a location with a distribution as required. As the size range is tuneable, the full magnetic properties from superparamagnetic, over single domain ferromagnetic, to multi-domain are covered.

Research paper thumbnail of ACCIDENT IDENTIFICAION AND THEFT AVOIDING SYSTEM USING EMBEDDED SYSTEM

Research paper thumbnail of Tomographic nanofabrication of ultrasharp three-dimensional nanostructures

Applied Physics Letters, 2008

We present the extension of electron tomography from a pure characterization technique into a thr... more We present the extension of electron tomography from a pure characterization technique into a three-dimensional nanofabrication technique using focused electron beams in the scanning transmission electron microscope. Two-dimensional surface patterning techniques are insufficient to achieve full three-dimensional nanosculpting, instead, multiple sample rotations under the beam are required. We demonstrate fabrication of ultrafine tips and hollow structures with applications in scanning probe microscopy, atom probe tomography, or in magnetoconductance of nanobridges. A sharpened tip radius of <3 nm is achieved, an order of magnitude finer than with standard methods.

Research paper thumbnail of A novel tripod-driven platform for in-situ positioning of samples and electrical probes in a TEM

Journal of Physics: Conference Series, 2010

... BD Medford1, BL Rogers1, D Laird1, N Berdunov1, AJ Lockwood2, T Gnanavel2, W Guan2, J Wang2, ... more ... BD Medford1, BL Rogers1, D Laird1, N Berdunov1, AJ Lockwood2, T Gnanavel2, W Guan2, J Wang2, G Möbus2, BJ Inkson2 and PH Beton1* 1 School of Physics &amp;amp;amp;amp; Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK 2Department of Engineering Materials ...

Research paper thumbnail of Nanoscale sculpting of ferromagnetic structures by electron beam ablation

Journal of Physics: Conference Series, 2010

Abstract. We report an electron beam (e-beam) fabrication method to produce sub-5 nm structures, ... more Abstract. We report an electron beam (e-beam) fabrication method to produce sub-5 nm structures, eg nanohole-arrays, nanojunctions and nanotips inside a TEM. The method is demonstrated using ferromagnetic nickel cross-sectional TEM specimens as well as electrochemically etched nickel tips. Different e-beam shapes and electron guns are compared, including point versus line focus and field-emission versus LaB6 guns. As an extension of this 2-D patterning of nanostructures, a 3-D nanofabrication technique has ...

Research paper thumbnail of Nanoporous structures from anodisation of non-planar aluminium surfaces

Journal of Physics: Conference Series, 2010

We report about a novel combination of two etching techniques for generating nanostructures, whic... more We report about a novel combination of two etching techniques for generating nanostructures, which individually are well established: (i) metal tip etching in NaOH, as e.g. used for STM or atom probe tip making, and (ii) anodic oxidation of aluminium for the generation of self-organised ordered pores. The non-planar geometry in both these etching processes allowed us to follow the

Research paper thumbnail of In-situ cobalt nanocrystal synthesis by intense electron beams in TEM

Journal of Physics: Conference Series, 2012

We report the synthesis of cobalt nanoparticles of a range of sizes from raw cobalt fluoride powd... more We report the synthesis of cobalt nanoparticles of a range of sizes from raw cobalt fluoride powder using high intensity focused electron beams and their characterisation in-situ in a TEM. A variety of beam intensities with different focussing level in a JEOL JEM 3010 TEM at an acceleration voltage of 300 kV is used. Depending on the beam intensity either a distribution of a large number of nanoparticles of 1-150 nm size or singular/a small number of fine metal particle(s) of ~150 nm up to micron size can be produced. Mechanisms of the nanoparticle formation are discussed. This simple, organic precursor free, non-hazardous and oxide-free fabrication method offers great potential for basic research, as it allows the fabrication of fresh particles "on demand" in a location with a distribution as required. As the size range is tuneable, the full magnetic properties from superparamagnetic, over single domain ferromagnetic, to multi-domain are covered.