http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nanocomposite ZnO–SnO <sub>2</sub> Nanofibers Synthesized by Electrospinning Method
Asokan, Kandasami,Park, JaeYoung,Choi, Sun-Woo,Kim, Sang Sub Springer 2010 NANOSCALE RESEARCH LETTERS Vol.5 No.4
<P>We report the characterization of mixed oxides nanocomposite nanofibers of (1 − <I>x</I>) ZnO-(<I>x</I>)SnO<SUB>2</SUB> (<I>x</I> ≤ 0.45) synthesized by electrospinning technique. The diameter of calcined nanofibers depends on Sn content. Other phases like SnO, ZnSnO<SUB>3</SUB>, and Zn<SUB>2</SUB>SnO<SUB>4</SUB> were absent. Photoluminescence studies show that there is a change in the blue/violet luminescence confirming the presence of Sn in Zn-rich composition. Present study shows that the crystalline nanocomposite nanofibers with stoichiometry of (1 − <I>x</I>)ZnO-(<I>x</I>)SnO<SUB>2</SUB> (<I>x</I> ≤ 0.45) stabilize after the calcination and possess some morphological and optical properties that strongly depend on Sn content.</P>
Controlling the Size of Nanograins in TiO2 Nanofibers
박재영,최선우,Kandasami Asokan,김상섭 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.5
The feasibility of controlling the size of nanograins in TiO2 nanofibers by varying the duration of calcination is demonstrated in this study. This result opens up a new dimension in understanding the physical properties of nanomaterials and their applications. Similar to the sintering behavior commonly observed in bulk ceramics,the nanograins in nanofibers grow in size under a longer calcination time.
Growth of nanograins in TiO2 nanofibers synthesized by electrospinning.
Park, Jae Young,Choi, Sun-Woo,Asokan, Kandasami,Kim, Sang Sub American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.5
<P>Present study focuses the effect of calcination temperature and its duration on the morphology and growth of nanograins in individual TiO2 nanofibers synthesized by electrospinning method. Polyvinyl acetate and titanium tetraisopropoxide were used as chemical precursors along with other standard solvents in the synthesis process. This study shows that synthesized TiO2 nanofibers are randomly arranged and spreads uniformly over the Si substrate and possess polycrystalline nature consisting of nanograins. Similar to the sintering behavior generally observed in bulk ceramics, the nanograins coalesce and grow under higher calcination temperature and longer calcination time. The activation energy for the growth of nanograins is found to be 47.2 kJ/mol. The dominant growth mechanism changes depending on the stages of calcination.</P>
Chemical effects at interfaces of Fe/MgO/Fe magnetic tunnel junction
Singh, Jitendra Pal,Kaur, Baljeet,Gautam, Sanjeev,Lim, Weon Cheol,Asokan, Kandasami,Chae, Keun Hwa Elsevier 2016 Superlattices and microstructures Vol.100 No.-
<P><B>Abstract</B></P> <P>Present review focuses the investigation carried out in order to understand the interface structure of magnetic tunnel junction (MTJ) by considering Fe/MgO/Fe as prototype structure. Tunneling magnetoresistence (TMR) of MTJ is affected by the spin polarization of ferromagnetic layers. This phenomena is governed by spin dependent tunneling in perfect MTJ. In MTJ with disordered interface, resonance states through interface play an important role. Some important phenomena like perpendicular magnetic anisotropy, spin transfer torques, and electrical switching are also affected by the interface structure. Apart from disorder and lattice mismatch, interface structure is governed by several factors like oxidation, defects, vacancies as well as hybridization among Fe(3<I>d</I>)-O(2<I>p</I>) states. These effects are categorized as ‘chemical effects’. Due to these factors, contribution from interface resonance states dominates which reduces TMR and related properties. A discussion for determination of these effects are highlighted using several techniques like X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Simulation results reveal modification of TMR via chemical effects occuring at interface in these MTJ. Thus tailoring of chemical effects in controlled manner is discussed to understand the interface assisted phenomena in these structures. Modification of the chemical effects is induced by irradiation of swift heavy ions, thereby, providing an opportunity to correlate chemical effects and TMR of MTJ.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Interface structure affects spin dependent tunneling. </LI> <LI> Chemical effects are dominant at interfaces. </LI> <LI> These effects can be tailored using swift heavy ion irradiation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Consequences of electronic excitations in CoFe1.90Dy0.10O4
Hemaunt Kumar,Jitendra Pal Singh,R.C. Srivastava,P. Negi,H.M. Agrawal,Kandasami Asokan,원성옥,채근화 한국물리학회 2015 Current Applied Physics Vol.15 No.12
Present work reports the irradiation induced effects in Dy3þ doped cobalt ferrite nanoparticles in the regime of dominant electronic excitation processes induced by 100 MeV O7þ ion irradiation. Irradiation leads to the deterioration of crystalline phase as envisaged by X-ray diffraction. Crystallite size decreases with the increase of irradiation fluence. Disappearance of certain bands in Raman spectra at higher fluence of irradiation confirms the crystalline disorder induced by electronic excitations. Fourier transform infrared spectra show onset of cation migration from tetrahedral site to octahedral site and vice versa. X-ray absorption fine structure measurements depict the preservation of valence state of metal ions after irradiation. These measurements further infer bond breaking process in irradiated materials. Magnetic measurements carried out on these materials indicate slight increase of saturation magnetization at room temperature followed by the decrease of coercive field. Obtained results are discussed on the basis of appropriate mechanism.