Search arXivSearch

arXiv · 2009.01733

Variation of TiO2/SiO2 mixed layers induced by different Xe+ ion energies

Abstract

The broadening and optical parameters of TiO2/SiO2 transition layers depending on the ion energy have been investigated using the Rutherford Backscattering Spectrometry (RBS) and Ellipstrometry Spectroscopy (ES) methods. The TiO2/SiO2 samples were irradiated by Xe+ ions with energies of 100, 150, 200 and 250 keV. The depth profiles of the elements determined by the RBS spectra show the structure and thickness of the TiO2/SiO2 transition layers before and after implantation. We have found that the thickness of the transition region between the TiO2 and SiO2 layers increases with the increasing incident ion energy. This phenomenon indicates an increasing amount of atomic mixing at the TiO2/SiO2 interface. In addition, the variation of transition layers could be explained by defect depth profiles and ions energy transferred in the mixed layers by means of SRIM calculations. The thickness obtained from the RBS is in good agreement with that measured using the ES method. Based on these obtained results, we have also investigated the optical constants of implanted and non-implanted TiO2/SiO2 structures. The wave forms measured with varying incident angles suggest that the measurements were made close to near the main principle point. The yields of ψand δbands vary at different incident angles, is associated with interference processes of the light reflected from the structures examined. The refractive index and the extinction coefficient were found to increase after implantation taking place up to 200-keV Xe and then decrease at 250 keV.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tran Van Phuc, Miroslaw Kulik, Afag Madadzada, Dorota. Kolodynska, Le Hong Khiem, Phan Luong Tuan, Nguyen Ngoc Anh. 2020-09-03. Variation of TiO2/SiO2 mixed layers induced by different Xe+ ion energies. https://arxiv.org/abs/2009.01733

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Incommensurate structural and magnetic modulations in potassium-rich cryptomelane, K$_x$Mn$_8$O$_{16}$ ($x\approx1.45$)

Cryptomelane is a hollandite-like material consisting of K$^+$ cations in an $α$-MnO$_2$ tunnel-like crystallographic motif. Cryptomelane with stoichiometry K$_x$Mn$_8$O$_{16}$ ($x\approx1.45$) has been synthesized and its magnetic properties investigated using variable-temperature magnetic susceptibility, heat capacity, and neutron powder diffraction. Three distinct transitions at $T_1=184$\,K, $T_2=54.5$\,K, and $T_3=24$\,K are observed. At $T_1$ there is a subtle tetragonal$\rightarrow$monoclinic transition associated with emergence of a set of non-magnetic superstructure peaks indexable to a $\vec{k}_\mathrm{struc}\approx0.74\vec{c^*}$ incommensurate modulation parallel to the $α$-MnO$_2$ tunnels. Our findings are consistent with a relation previously reported in titanate hollandites, that $x\approx2|\vec{k}_\mathrm{struc}|$. Magnetic Bragg peaks emerge below $T_2=54.5$\,K, and their positions indicate an incommensurate modulated magnetic structure. The model consistent with the data is a dual-$\vec{k}_\mathrm{mag}$ structure with a ferromagnetic $|\vec{k}_\mathrm{mag}|=0$ component and an incommensurate $\vec{k}_\mathrm{mag}\approx0.37\vec{c^*}$, with the latter most likely to be helical. The period of oscillation of the incommensurate magnetic component is in line with predictions based on a Heisenberg spin Hamiltonian [Mandal \textit{et al}. Phys. Rev. B 90, 104420 (2014)]. Below $T_3=24$\,K, there is a magnetic transition, which gives rise to a different set of magnetic Bragg peaks indicative of a highly complex magnetic structure.

cond-mat.mtrl-sci

An anisotropic functional for two-dimensional material systems

Density function theory is the workhorse of modern electronic structure theory. However, its accuracy in practical calculations is limited by the choice of the exchange-correlation potential. In this respect, two-dimensional materials pose a special challenge, as all these materials and their heterostructures have a crucial similarity. The underlying atomic structures are strongly spatially inhomogeneous, implying that current exchange-correlation functionals, that in almost all cases are isotropic, are ill-prepared for an accurate description. We present an anisotropic screened-exchange potential, that remedies this problem and reproduces the band-gap of 2D materials as well as the piecewise linearity of the total energy with fractional occupation number.

cond-mat.mtrl-sci

Thermally-driven reorientation of the Néel vector in altermagnetic MnTe

Altermagnets are novel magnetic systems that possess a spin-polarized electronic band structure without a net magnetic moment, making them promising for device applications. Hexagonal MnTe, a prototypical altermagnet, arguably exhibits the most properties consistent with theoretical predictions, including an anomalous Hall effect despite a vanishing net magnetization, and altermagnetinduced electronic band splitting. However, fundamental questions remain, including why some effects only appear significantly below the magnetic ordering temperature. Here, we resolve this discrepancy by revealing a reorientation of the Néel vector in single-crystalline MnTe. The Néel vector points 30° from the a-axis at low $T$, before aligning directly with the a-axis around $T\simeq 260$ K. We attribute this to single-ion anisotropy, which depends on temperature-dependent lattice parameters. We obtained these results using muon-spin spectroscopy, magnetization measurements, and X-ray diffraction; we show that the findings are consistent with neutron diffraction. Manipulating this effect, for example through strain, could unlock sensitive electronic detection schemes for external stimuli, paving the way for functional altermagnetic devices.

cond-mat.mtrl-sci