共查询到7条相似文献,搜索用时 0 毫秒
1.
Shiv P. Patel A.K. Chawla Ramesh Chandra Jai Prakash P.K. Kulriya J.C. Pivin D. Kanjilal Lokendra Kumar 《Solid State Communications》2010,150(25-26):1158-1161
Zinc sulfide (ZnS) thin films in zinc-blende (ZB) and wurtzite (W) phases have been fabricated by pulsed laser deposition. 150 MeV Ni ion beam irradiation has been carried out at different fluences ranging from 1011 to 1013 ions/cm2 at room temperature for ion induced modifications. Structural phase transformation in ZnS from W to ZB phase is observed after high energy ion irradiation which leads to the decrease in bandgap. Generation of high pressure and temperature by thermal spike during MeV ion irradiation along the ion trajectory in the films is responsible for the structural phase transformation. 相似文献
2.
Shiv P. Patel J.C. Pivin M.K Patel Jonghan Won Ramesh Chandra D. Kanjilal Lokendra Kumar 《Journal of magnetism and magnetic materials》2012
The effect of swift heavy ions (SHI) on magnetic ordering in ZnS thin films with Co ions substituted on Zn sites is investigated. The materials have been synthesized by pulsed laser deposition on substrates held at 600 °C for obtaining films with wurtzite crystal structure and it showed ferromagnetic ordering up to room temperature with a paramagnetic component. 120 MeV Ag ions have been used at different fluences of 1×1011 ions/cm2 and 1×1012 ions/cm2 for SHI induced modifications. The long range correlation between paramagnetic spins on Co ions was destroyed by irradiation and the material became purely paramagnetic. The effect is ascribed to the formation of cylindrical ion tracks due to the thermal spikes resulting from electron–phonon coupling. 相似文献
3.
P. Mallick S. Majumder D.C. Agarwal D.K. Avasthi N.C. Mishra 《Applied Surface Science》2009,256(2):521-523
NiO nanoparticle thin films grown on Si substrates were irradiated by 107 MeV Ag8+ ions. The films were characterized by glancing angle X-ray diffraction and atomic force microscopy. Ag ion irradiation was found to influence the shape and size of the nanoparticles. The pristine NiO film consisted of uniform size (∼100 nm along major axis and ∼55 nm along minor axis) elliptical particles, which changed to also of uniform size (∼63 nm) circular shape particles on irradiation at a fluence of 3 × 1013 ions cm−2. Comparison of XRD line width analysis and AFM data revealed that the particles in the pristine films are single crystalline, which turn to polycrystalline on irradiation with 107 MeV Ag ions. 相似文献
4.
K. Narumi Y. Xu K. Miyashita H. Naramoto 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):385-388
We report a new effect of ion irradiation on
C60 thin films:
C60 thin films irradiated with 7-MeV
C2+ ions show resistance to
photopolymerization. The resistance increases with increasing
ion fluence of irradiation. The effect is qualitatively
explained by the fact that the number of a
C60 pair satisfying the topochemical
requirement for photochemical reaction in solids decreases by
destruction of C60 molecules accompanied
by lattice disorder. 相似文献
5.
Three phase transitions (face centered to simple cubic, surface rearrangement from (2×2) to (1×1) and glass transition) in fullerene thin films and the effect of 150 MeV Ti ion irradiation on these transitions have been studied, using temperature dependence of electrical resistivity measurements. The structural properties of the C60 thin films are studied by X-ray diffraction, atomic force microscopy and UV-vis spectroscopy. It is observed that defect creation by ion irradiation in the films lead to quenching and broadening of structural phase transitions but the transition temperatures did not show significant shifting under ion irradiation. 相似文献
6.
We report the observation of a propounced peak in surface resistance at microwave frequencies of 4.88 GHz and 9.55 GHz and
its disappearance after irradiation with swift ions in laser ablated DyBa2Cu3O7-δ (DBCO) thin films. The measurements were carried out in zero field as well as in the presence of magnetic fields (up to 0.8
T). The films were irradiated using 90 MeV oxygen ions at Nuclear Science Centre, New Delhi at a fluence of 3×1013 ions/cm2. Introduction of point defects and extended defects after irradiation suppresses the peak at 9.55 GHz whereas no suppression
is observed at 4.88 GHz. These results and the vortex dynamics in the films at microwave frequencies before and after irradiation
are discussed. 相似文献
7.
Vishnu Chauhan T. Gupta Paramjit Singh P.D. Sahare N. Koratkar Rajesh Kumar 《Physics letters. A》2019,383(9):898-907
The calibrated and controlled swift heavy ions (SHI) beam irradiation generate defects which can cause modifications in various properties of the materials such as structural, optical, magnetic, morphological, and chemical etc. The passage of ion through the target material causes the nuclear energy losses () and electronic energy losses (). The dominates over in SHI irradiation. In the present study, ZrO2 thin films were grown on silicon and glass substrate by using RF sputtering deposition technique. For the purpose of modifications induced by swift heavy ions, these films were irradiated by a 120 MeV S9+ ion beam of 1 pnA current, with varying ion fluences from 5E12 to 1E13 ions/cm2, using the tandem accelerator at the Inter University Accelerator Center (IUAC), New Delhi, India. The X-ray diffraction (XRD) patterns confirmed the formation of monoclinic and tetragonal phases and it was observed that XRD peaks intensity increased up to the fluence of 5E12 ions/cm2 followed by opposite behavior at higher fluences. Atomic force microscope (AFM) study revealed the increased surface roughness after SHI irradiation. In addition to it, the formation of electronic transition states in optical band gap region and enhancement of absorption edge was observed from UV-visible spectroscopy (UV-Vis) results due to which direct band gap energy value decreased from those of un-irradiated samples. Photoluminescence (PL) broad emission spectra were determined using the excitation wavelength at 290 nm with the prominent peak at 415 nm which can be ascribed to Zr vacancies due to band edge emission as a result of free-exciton recombination. Rutherford backscattering spectrometry (RBS) technique was used for depth profiling and elemental composition in zirconia thin films. The expected role of electronic energy loss during ion irradiation is to modify the properties of the material has been discussed. 相似文献