Dr. Shavkat Akhmadaliev

Head Accelerator
Phone: +49 351 260 3284

Publications - Ion accelerators

Here you are finding current publications that have emerged from user experiments and collaborations with our group.

Year incl. Online First >= 2021
"Online First" included
First HDZR Author OU: Accelerator (FWIZ-B)

Obvious phase transition status induced by He+-ions implantation in KTN crystal

Yang, Q.; Li, X.; Liu, H.; Zheng, D.; Akhmadaliev, S.; Zhou, S.; Wu, P.

We report on the formation of a critical ferroelectric state induced by the He+ ion implantation in potassium tantalate niobate crystal. Obvious phase change has been observed in the ion irradiated region, which is mostly related to the stable polarized nanometric regions formed during the ion implantation process. Under the irradiation of 2 MeV He+ ions, two distinguishable layers corresponding to different energy transfer modes (elastic nuclear collision and inelastic electronic collision, respectively) between the incident He+ ions and the intrinsic lattices have been formed beneath the irradiated surface. Lattice dynamics before and after the ion implantation process are investigated by the confocal μ-Raman system. And the variations of typical Raman-active vibrational modes demonstrate the presence of lattice distortion in the irradiated region. X-ray diffraction experiments further suggest the mostly uniform lattice elongation in this region. Piezo-response force characteristic measurements reveal the existence of stable polarized nanometric regions with more intense polarization and verify that the crystal with such a phase status possesses extraordinary microscopic disorders, which is different from the traditional ferroelectric or paraelectric phase. Optical transmission experiments demonstrate that the irradiated region possesses relatively low propagation loss. The ion implantation method provides a new approach to form a temperature-stable critical ferroelectric state in relaxor ferroelectric materials. Analyses of the modification on the lattice dynamics of the irradiated region can help us build a clear awareness of the physical essence of this critical state and the relaxor ferroelectricity. Also, with good optical transmittance, the irradiated region is capable of promising optical functional devices.

Keywords: Implantation/irradiation; Ferroelectric; Relaxor; Phase stability; Polarized nanometric regions

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Post-implantation defects in heavy ion implanted monocrystalline ZnO

Werner, Z.; Barlak, M.; Ratajczak, R.; Akhmadaliev, S.; Heller, R.; Staszkiewicz, B.; Zagórski, J.

Monocrystalline ZnO samples were implanted with Co (transition metal) and with Ar and Kr noble gas ions, with energies and doses leading to comparable damage in the host lattice as regards its extension and magnitude. Structural properties of the implantedZnOwere investigated by channeled Rutherford Backscattering Spectrometry (cRBS), aided with calculations using McChasy code. It was shown that the damage produced by implantation does not reach an amorphization level in all cases and is produced deeper in the crystal in comparison with theoretical predictions. The range and magnitude of damaged region are comparable in all cases of ion implantation.

Keywords: ZnO; heavy ion implantation; cRBS measurements; damage simulation

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