Zoran Popovic

Zoran Popovic
Institute of Physics Belgrade | IPB · Center for Solid State Physics and New Materials

PhD

About

318
Publications
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4,458
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Publications

Publications (318)
Preprint
Full-text available
A Raman scattering study covering the entire substitution range of the FeSe$_{1-x}$S$_x$ solid solution is presented. Data were taken as a function of sulfur concentration $x$ for $0\le x \le 1$, of temperature and of scattering symmetry. All type of excitations including phonons, spins and charges are analyzed in detail. It is observed that the en...
Article
Full-text available
The surface morphology and structure of zinc oxide thin films play a key role in many applications such as chemical sensors and photocatalysts. In this study, ZnO thin films are prepared on Si/SiO2 substrates by spin-coating sol–gel technique. New element in the films preparation is the application of drying with hot air flow (Th= 90–95 °C), as fir...
Article
We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in 1T−TaS2 single crystals, supported by ab initio calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows P3¯ symmetry of the system, thus excluding the previously prop...
Preprint
Full-text available
We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in $1T$-TaS$_2$ single crystals, supported by \textit{ab initio} calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows $\mathrm{P3}$ symmetry of the system, thus exclu...
Article
We present a detailed investigation of the crystal structure of VI3, a two-dimensional van der Waals material of interest for studies of low-dimensional magnetism. As opposed to the average crystal structure that features R3̅ symmetry of the unit cell, our Raman scattering and X-ray atomic pair distribution function analysis supported by density fu...
Preprint
In all Fe superconductors the maximal $T_c$ correlates with the average anion height above the Fe plane, i.e. with the geometry of the FeAs$_4$ or FeCh$_4$ (Ch = Te, Se, S) tetrahedron. By synthesizing FeSe$_{1-x}$S$_x$ (0 $\leq$ x $\leq$ 1) single crystal alloys and by performing a series of experiments we find that $T_c$ does scale with the avera...
Article
We report temperature‐dependent Raman scattering and magnetization studies of van der Waals ferromagnetic compound CrSi0.8Ge0.1Te3. Magnetic susceptibility measurements revealed dominant ferromagnetic interactions below TC which shift to the lower values due to the presence of vacancies. A Raman active mode, additional to the ones predicted by symm...
Preprint
Full-text available
In this work we report on the controlled fabrication of a self-assembled line network in highly epitaxial BiFeO3 thin films on top of LaAlO3 in the kinetically limited grown region by RF sputtering. As previously shown in the case of manganite thin films, the remarkable degree of ordering is achieved using vicinal substrates with well-defined step-...
Article
Full-text available
In this work we report on the controlled fabrication of a self-assembled line network in highly epitaxial BiFeO3 thin films on top of LaAlO3 in the kinetically limited grown region by RF sputtering. As previously shown in the case of manganite thin films, the remarkable degree of ordering is achieved using vicinal substrates with well-defined step-...
Article
We present Raman spectroscopy measurements of the van der Waals bonded ferromagnet Fe3−xGeTe2, together with lattice dynamics. Four out of eight Raman active modes are observed and assigned, in agreement with numerical calculations. The energies and linewidths of the observed modes display an unconventional temperature dependence at about 150 and 2...
Preprint
We present Raman spectroscopy measurements of the van der Waals bonded ferromagnet Fe$_{3-x}$GeTe$_2$, together with lattice dynamics. Four out of eight Raman active modes are observed and assigned, in agreement with numerical calculations. The energies and line-widths of the observed modes display an unconventional temperature dependence at about...
Article
We report a temperature- and magnetic-field-dependent Raman-scattering study of the spin-ladder compound BaFe2Se2O. Temperature evolution of the B1g mode self-energies revealed anomalous behavior at about 100 and 240 K with strong temperature-dependent Fano asymmetry. Furthermore, the Ag modes integrated intensity exhibits an additional change in t...
Article
We have employed micro-Raman spectroscopy to get insight into intrinsic biomolecular profile of individual mesenchymal stem cell isolated from periodontal ligament. Furthermore, these cells were stimulated towards adipogenic, chondrogenic, and osteogenic lineages and their status of differentiation was assessed using micro-Raman spectroscopy. In bo...
Article
The scope of this paper is temperature dependence of Raman spectra in several nanocrystalline materials and iron‐based single‐crystals. The Raman results presented and analyzed here are related to TiO2 nanopowders (with dominant anatase and brookite phase) and ZnxCd1−xSe single layers measured at different temperatures. Temperature‐dependent Raman...
Article
In investigation of (patho)physiological processes, cells represent frequently used analyte as an exceptional source of information. However, spectroscopic analysis of live cells is still very seldom in clinics, as well as in research studies. Among others, the reasons are long acquisition time during which autolysis process is activated, necessity...
Article
Full-text available
The charge and spin dynamics of the structurally simplest iron-based superconductors, FeSe, may hold the key to understanding the physics of high temperature superconductors in general. Unlike in the iron pnictides, long range magnetic order is not found in FeSe in spite of the observation of the same structural transition around 90\,K. In this stu...
Conference Paper
Full-text available
First results on the effect of laser irradiation of sol gel ZnO thin films deposited on top of Si-SiO2(300 nm) substrates are reported. Postdeposiion annealing of all films is carried out at 400oC in air and a part of the annealed films are irradiated with nanosecond pulse laser (wavelength of 1064 nm, fluences in the range 25 - 500 mJ/cm2). The no...
Article
The vibrational properties of CrI3 single crystals were investigated using Raman spectroscopy and were analyzed with respect to the changes of the crystal structure. All but one mode are observed for both the low-temperature R3¯ and the high-temperature C2/m phase. For all observed modes the energies and symmetries are in good agreement with DFT ca...
Article
We present Raman scattering results on the layered semiconducting ferromagnetic compound CrSiTe3. Four Raman-active modes, predicted by symmetry, are observed and assigned. The experimental results are supported by density functional theory calculations. The self-energies of the Ag3 and the Eg3 symmetry modes exhibit unconventional temperature evol...
Preprint
Full-text available
We present the Raman scattering results on layered 2D semiconducting ferromagnetic compound CrSiTe$_3$. Four Raman active modes, predicted by symmetry, have been observed and assigned. The experimental results are supported by DFT calculations. The self-energies of the $A_g^3$ and the $E_g^3$ symmetry modes exhibit unconventional temperature evolut...
Preprint
Full-text available
The vibrational properties of $\mathrm{CrI_3}$ single crystals were investigated using Raman spectroscopy and were analyzed with respect to the changes of the crystal structure. All but one mode are observed for both the low-temperature $R\bar{3}$ and the high-temperature C2/$m$ phase. For all observed modes the energies and symmetries are in good...
Article
Full-text available
We present results from light scattering experiments on tetragonal FeS with the focus placed on lattice dynamics. We identify the Raman active A1g and B1g phonon modes, a second order scattering process involving two acoustic phonons, and contributions from potentially defect-induced scattering. The temperature dependence between 300 and 20K of all...
Poster
Full-text available
Abstract. The titanium dioxide (TiO2) nanotubes with high-specific surface area, ion-exchangeable ability, and photocatalytic property have been considered for various potential applications as photocatalysis, electro chromic device, hydrogen generation, corrosion resistance, solar cells, sensors, wettability, and especially in the biomedical field...
Article
Full-text available
Raman scattering spectra of zigzag spin chain TaFe1.25Te3 single crystal are presented in a temperature range from 80 to 300 K. Nine Raman active modes of Ag and Bg symmetry are clearly observed and assigned by probing different scattering channels, which is confirmed by lattice dynamics calculations. Temperature dependence of the Raman modes linew...
Poster
Full-text available
Beta-blockers pose a hazard to the environment and there is an ongoing search for the efficient method for their degradation. Under suitable preparation conditions, titania - based nanopowders show promise as photocatalysts for degradation of pindolol (selected β-blocker). To find the material properties suitable for rapid degradation of this β-blo...
Article
Full-text available
The effect of 20 MeV electron irradiation on the room temperature photoluminescence from homogeneous SiOx and composite Si-SiOx films, containing amorphous or crystalline Si nanoparticles, is studied. Layers with x = 1.5 and 1.7 and thickness of 200 nm were deposited on crystalline silicon substrates by thermal evaporation of SiO in vacuum. Film an...
Article
Full-text available
We present a single-step route to generate ordered nanocomposite thin films of secondary phase inclusions (Mn3O4) in a pristine perovskite matrix (LaMnO3) by taking advantage of the complex phase diagram of manganese oxides. We observed that in samples grown under vacuum growth conditions from a single LaMnO3 stoichiometric target by Pulsed Laser D...
Article
We present a study of charge density wave (CDW) ordering in CeTe$_3$ at room temperature using a scanning tunneling microscope and Raman spectroscopy. Two characteristic CDW ordering wavevectors obtained from the Fourier analysis are assessed to be $|{\bf \textbf{c}}^\ast-{\bf q}|=4.19\,{\rm nm}^{-1}$ and $|{\bf q}|=10.26\,{\rm nm}^{-1}$ where $|{\...
Article
Polarized Raman scattering spectra of the K_xCo_{2-y}Se_2 single crystals reveal the presence of two phonon modes, assigned as of the A_{1g} and B_{1g} symmetry. Absence of additional modes excludes the possibility of vacancy ordering, unlike in K_xFe_{2-y}Se_2. The ferromagnetic (FM) phase transition at T_c\approx 74 K leaves a clear fingerprint o...
Article
Full-text available
Homogeneous SiOx films (x=1.3, 200 nm and 1000 nm thick) and composite a-Si-SiOy films (y ~ 1.80) containing amorphous Si nanoparticles have been prepared on crystalline (c-Si) substrate. A part of the films was irradiated at temperature below 50°C by 20 MeV electrons with two different fluences (7.2x1014 and 1.44x1015 el.cm-2). Atomic force micros...
Article
Full-text available
We present Co substitution effects in KxFe2-y-zCozSe2 (0.06≤z≤1.73) single-crystal alloys. By 3.5% of Co doping superconductivity is suppressed, whereas phase separation of semiconducting K2Fe4Se5 and superconducting/metallic KxFe2Se2 is still present. We show that the arrangement and distribution of the superconducting phase (stripe phase) are con...
Article
Full-text available
Polarized Raman scattering spectra of superconducting Kx Fe2−y Se2 and non-superconducting K0.8Fe1.8Co0.2Se2 single crystals were measured in the temperature range from 10 K up to 300 K. Two Raman active modes from the I4/mmm phase and seven from the I4/m phase are observed in the frequency range from 150 to 325 cm−1 in both compounds, suggesting t...
Article
We report electron doping effects by Ni in ${\text{K}}_{x}{\text{Fe}}_{2$-${}$\delta${}$-${}y}{\text{Ni}}_{y}{\text{Se}}_{2}\phantom{\rule{4pt}{0ex}}(0.06$\le${}y$\le${}1.44)$ single-crystal alloys. A rich ground-state phase diagram is observed. A small amount of Ni ($$\sim${}4$%) suppressed superconductivity below 1.8 K, inducing insulating spin-g...
Article
Full-text available
We present the Raman scattering spectra of the ${\mathrm{BaFe}}_{2}{\mathrm{X}}_{3}\phantom{\rule{0.28em}{0ex}}(\mathrm{X}\phantom{\rule{0.28em}{0ex}}=\phantom{\rule{0.28em}{0ex}}\mathrm{S},\phantom{\rule{0.28em}{0ex}}\mathrm{Se})$ compounds in a temperature range between 20 and 400 K. Although the crystal structures of these two compounds are both...
Article
Full-text available
We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce1−x Cu x O2−y (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm−1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution...
Conference Paper
Full-text available
The effect of 20 MeV electron irradiation on the vibrational properties of homogeneous SiOx films and SiOx films containing amorphous or crystalline Si nanoparticles is studied. Layers with x = 1.15 and 1.3 and two different thicknesses, 200 nm and 1000 nm, were deposited on crystalline silicon substrates and annealed at 250 °C for stabilization. N...
Article
Raman scattering spectra of Fe1+yTe1−xSexFe1+yTe1−xSex (x =0, y =0.07; x =0.1, y =0.05 and x =0.4, y =0.02) alloys are measured in a temperature range between 20 K and 300 K. The A1gA1g and B1gB1g Raman active modes have been experimentally observed at energies 156 and 198 cm−1, which is in rather good agreement with the lattice dynamics calculatio...
Article
Full-text available
Polarized Raman scattering measurements on IrTe2 single crystals carried out over the 15-640 K temperature range, and across the structural phase transition, reveal different insights regarding the crystal symmetry. In the high temperature regime three Raman active modes are observed at all of the studied temperatures above the structural phase tra...
Article
We report the low-temperature Raman scattering study of racemic ibuprofen. Detailed analysis of the racemic ibuprofen crystal symmetry, related to the vibrational properties of the system, has been presented. The first principle calculations of a single ibuprofen molecule dynamical properties are compered with experimental data. Nineteen, out of 26...
Article
Full-text available
Raman scattering spectra of new Fe-based S=2 spin ladder compound BaFe$_2$Se$_2$O are measured in a temperature range between 15 K and 623 K. All six A$_{1g}$ and two B$_{1g}$ Raman active modes of BaFe$_2$Se$_2$O, predicted by the factor-group analysis, have been experimentally observed at energies that are in a rather good agreement with the latt...
Article
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Article
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Abstract In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT) and modified glycine/nitrate procedure (MGNP). Different types of solid solutions with rare earth dopant...
Article
Ce1−xFexO2−y (0≤x≤0.05) nanopowders were synthesized using hydrothermal method at low calcination temperature and low doping regime. Structural and morphological characterization has been carried out by the X-ray diffraction method and non-contact atomic force microscopy. Vibrational properties were investigated by Raman spectroscopy. It was observ...
Article
Full-text available
We report first-principles calculations of the lattice dynamics of KNi2Se2 together with Raman scattering study. We have observed three out of four Raman-active modes predicted by factor group analysis. Calculated phonon frequencies are in good agreement with experimental findings. Contrary to its iron counterpart (KxFe2-ySe2), K0.95Ni1.86Se2 does...
Article
Ce 1 À x Fe x O 2 À y (0r xr 0.05) nanopowders were synthesized using hydrothermal method at low calcination temperature and low doping regime. Structural and morphological characterization has been carried out by the X-ray diffraction method and non-contact atomic force microscopy. Vibrational properties were investigated by Raman spectroscopy. It...
Article
Full-text available
We have measured the magnetization of undoped and Fe(2+/3+) doped CeO(2-y) nanocrystals at various temperatures and magnetic fields. The Stoner condition N(0)I > 1 is multiply fulfilled in the case of nano-CeO(2-y), favoring the band ferromagnetism approach. In the case of Fe-doped samples, the magnetization versus magnetic field dependence is well...
Article
Full-text available
Polarized Raman scattering spectra of KxFe2−ySe2 were analyzed in terms of peculiarities of both I4/m and I4/mmm space group symmetries. The presence of the Raman active modes from both space group symmetries (16 Raman-active modes of the I4/m phase and two Raman-active modes of the I4/mmm phase) confirmed the existence of two crystallographic doma...
Article
Full-text available
Ce(1-x)Pr(x)O(2-δ) (0 ≤ x ≤ 0.4) nanocrystals were synthesized by self-propagating method and thoroughly characterized using X-ray diffraction, Raman and X-ray photoelectron spectroscopy and magnetic measurements. Undoped CeO₂ nanocrystals exhibited intrinsic ferromagnetism at room temperature. Despite the increased concentration of oxygen vacancie...
Article
Full-text available
The lattice dynamics of FeSb(2) is investigated by first-principles density functional theory calculations and Raman spectroscopy. All Raman- and infrared-active phonon modes are properly assigned. The calculated and measured phonon energies are in good agreement. We have observed strong mixing of the A(g) symmetry modes, with the intensity exchang...
Article
Nanocrystalline multilayers from ZnSe/Zn0.6Cd0.4Se with three different layer thicknesses (3.5, 5.0, 10.0 nm) and, for comparison, 400 nm thick Zn0.6Cd0.4Se nanocrystalline single layers have been prepared by thermal evaporation of ZnSe and CdSe in vacuum. Raman scattering spectra have been measured in the range 100–1000 cm−1 under excitation with...