Pub Date : 2024-05-13DOI: 10.1007/s13538-024-01491-1
Manisha Priyadarsini, Sobha Poonam Ekka, Dinesh Kumar Pati, Tanmaya Badapanda, B. Behera, R. Padhee
A series of novel lead free tungsten bronze (T-B) structured Ba4(La2-xBix)Fe2Nb8O30(x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) were formulated by traditional high temperature solid-state method and calcined at 1200 °C. The structural property was investigated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Tetragonal structure was confirmed from Rietveld analysis. The scanning electron micrograph (SEM) shows uniform distribution of rod-shaped grains with less porosity. The UV–vis analysis shows that the materials have band gaps in the range 2.17–2.29 eV which makes them useful for photocatalytic applications. The dielectric measurement of the samples was carried out in a broad range of frequency as well as temperature. The impedance of the materials falling off with the rise in temperature showing their negative temperature coefficient (NTCR) behavior. The variation of polarization with electric field confirms the ferroelectric nature of the samples.
采用传统的高温固态法配制了一系列新型无铅钨青铜(T-B)结构 Ba4(La2-xBix)Fe2Nb8O30(x = 0、0.05、0.1、0.15、0.2 和 0.25),并在 1200 °C 煅烧。通过 X 射线衍射(XRD)和傅立叶变换红外光谱(FTIR)对其结构特性进行了研究。通过里特维尔德分析,确认了四边形结构。扫描电子显微镜(SEM)显示,棒状晶粒分布均匀,孔隙率较低。紫外-可见光分析表明,这些材料的带隙在 2.17-2.29 eV 范围内,因此可用于光催化应用。样品的介电测量是在很宽的频率和温度范围内进行的。材料的阻抗随着温度的升高而下降,显示出它们的负温度系数(NTCR)特性。极化随电场的变化证实了样品的铁电性质。
{"title":"Structural, Electrical, and Optical Properties of Lead-Free TB Compound: Ba4(La2-xBix)Fe2Nb8O30 (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25)","authors":"Manisha Priyadarsini, Sobha Poonam Ekka, Dinesh Kumar Pati, Tanmaya Badapanda, B. Behera, R. Padhee","doi":"10.1007/s13538-024-01491-1","DOIUrl":"https://doi.org/10.1007/s13538-024-01491-1","url":null,"abstract":"<p>A series of novel lead free tungsten bronze (T-B) structured Ba<sub>4</sub>(La<sub>2-x</sub>Bi<sub>x</sub>)Fe<sub>2</sub>Nb<sub>8</sub>O<sub>30</sub>(x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) were formulated by traditional high temperature solid-state method and calcined at 1200 °C. The structural property was investigated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Tetragonal structure was confirmed from Rietveld analysis. The scanning electron micrograph (SEM) shows uniform distribution of rod-shaped grains with less porosity. The UV–vis analysis shows that the materials have band gaps in the range 2.17–2.29 eV which makes them useful for photocatalytic applications. The dielectric measurement of the samples was carried out in a broad range of frequency as well as temperature. The impedance of the materials falling off with the rise in temperature showing their negative temperature coefficient (NTCR) behavior. The variation of polarization with electric field confirms the ferroelectric nature of the samples.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-11DOI: 10.1007/s13538-024-01481-3
Huo Rui, Wang Hong
The growing rate of bump-on-tail instability has been investigated in unmagnetized plasma with Cairns distribution. The growing rate depends significantly on the number density ratio n1/n2, temperature ratio T1/T2, and the nonthermal parameter α. The influence of these parameters on the maximum growing rate is analyzed numerically by using solar data. The higher α can enhance the growing rate of bump-on-tail instability. The maximum growth rate also will increase with the decrease of number density ratio n1/n2 and the increase of temperature ratio T1/T2. These interesting results will be helpful for understanding some phenomena in space plasma.
{"title":"Bump-on-Tail Instability in Cairns Distributed Plasma","authors":"Huo Rui, Wang Hong","doi":"10.1007/s13538-024-01481-3","DOIUrl":"https://doi.org/10.1007/s13538-024-01481-3","url":null,"abstract":"<p>The growing rate of bump-on-tail instability has been investigated in unmagnetized plasma with Cairns distribution. The growing rate depends significantly on the number density ratio <i>n</i><sub>1</sub>/<i>n</i><sub>2</sub>, temperature ratio <i>T</i><sub>1</sub>/<i>T</i><sub>2</sub>, and the nonthermal parameter <i>α</i>. The influence of these parameters on the maximum growing rate is analyzed numerically by using solar data. The higher <i>α</i> can enhance the growing rate of bump-on-tail instability. The maximum growth rate also will increase with the decrease of number density ratio <i>n</i><sub>1</sub>/<i>n</i><sub>2</sub> and the increase of temperature ratio <i>T</i><sub>1</sub>/<i>T</i><sub>2</sub>. These interesting results will be helpful for understanding some phenomena in space plasma.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-10DOI: 10.1007/s13538-024-01476-0
Hongsheng Chen, Zhong Zheng
Random packing of binary mixtures of spherical particles in viscous fluid is numerically investigated via CFD-DEM, where moderate size ratios (d/D) are specially considered. Results indicate that binary packing in fluid is much looser than that in the absence of fluid, and two distinct phenomena can be identified as the global packing density varies with the volume fraction of coarse particle (XD). For small size ratios, the global packing density first increases with increasing XD due to the occupation mechanism, and then it reaches the maximum value when XD ≈ 0.6, beyond which the global packing density decreases as XD increases further. However, for large size ratios, the global packing density always decreases with increasing XD. These phenomena are further discussed by using the local packing density determined by Voronoi tessellation, the mean and local coordination number, and radial distribution function, with which the particle arrangements within binary mixtures are well identified.
{"title":"Binary Packing of Spherical Particles with Moderate Size Ratios in Viscous Fluid: A CFD-DEM Study","authors":"Hongsheng Chen, Zhong Zheng","doi":"10.1007/s13538-024-01476-0","DOIUrl":"https://doi.org/10.1007/s13538-024-01476-0","url":null,"abstract":"<p>Random packing of binary mixtures of spherical particles in viscous fluid is numerically investigated via CFD-DEM, where moderate size ratios (d/D) are specially considered. Results indicate that binary packing in fluid is much looser than that in the absence of fluid, and two distinct phenomena can be identified as the global packing density varies with the volume fraction of coarse particle (<i>X</i><sub><i>D</i></sub>). For small size ratios, the global packing density first increases with increasing <i>X</i><sub><i>D</i></sub> due to the occupation mechanism, and then it reaches the maximum value when <i>X</i><sub><i>D</i></sub> ≈ 0.6, beyond which the global packing density decreases as <i>X</i><sub><i>D</i></sub> increases further. However, for large size ratios, the global packing density always decreases with increasing <i>X</i><sub><i>D</i></sub>. These phenomena are further discussed by using the local packing density determined by Voronoi tessellation, the mean and local coordination number, and radial distribution function, with which the particle arrangements within binary mixtures are well identified.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-10DOI: 10.1007/s13538-024-01492-0
Vipin Kumar, Sanjeev K. Srivastava, Ravinder Kumar
In this communication, the design of broad band optical reflector and selective polarization filter using a one-dimensional photonic crystal (1D-PC) containing superconductor and semiconductor layer has been proposed and investigated theoretically. The proposed design consists of alternate layers of yttrium barium copper oxide YBa2Cu3O7 (YBCO) and silicon (Si), respectively. The refractive indices of YBCO and Si layers are modulated as the function of temperature and wavelength both. This characteristic brings this study closer to actual physical implementation. To obtain the reflectance and transmittance properties of the proposed structure and to analyze the propagation characteristics of electromagnetic waves, the transfer matrix method (TMM) has been employed. The analysis of the reflectance spectra shows that near the critical temperature of YBCO layers no broad band reflection (from 0 to 85°) is observed. On the other hand, when the temperature is lowered below the critical temperature, ODR arises. The proposed YBCO/Si structure gives a broad band reflection band (from 1394 to 1621 nm (bandwidth 227 nm)) for both TE and TM modes of polarizations at 85 K. Also, at higher incident angles, the proposed structure acts as a selective polarization-based filter without introducing any defect in the geometry.
{"title":"Optical Reflector and Selective Polarization Filter Based on 1D-Photonic Crystal Containing Si-YBCO Layer","authors":"Vipin Kumar, Sanjeev K. Srivastava, Ravinder Kumar","doi":"10.1007/s13538-024-01492-0","DOIUrl":"https://doi.org/10.1007/s13538-024-01492-0","url":null,"abstract":"<p>In this communication, the design of broad band optical reflector and selective polarization filter using a one-dimensional photonic crystal (1D-PC) containing superconductor and semiconductor layer has been proposed and investigated theoretically. The proposed design consists of alternate layers of yttrium barium copper oxide YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub> (YBCO) and silicon (Si), respectively. The refractive indices of YBCO and Si layers are modulated as the function of temperature and wavelength both. This characteristic brings this study closer to actual physical implementation. To obtain the reflectance and transmittance properties of the proposed structure and to analyze the propagation characteristics of electromagnetic waves, the transfer matrix method (TMM) has been employed. The analysis of the reflectance spectra shows that near the critical temperature of YBCO layers no broad band reflection (from 0 to 85°) is observed. On the other hand, when the temperature is lowered below the critical temperature, ODR arises. The proposed YBCO/Si structure gives a broad band reflection band (from 1394 to 1621 nm (bandwidth 227 nm)) for both TE and TM modes of polarizations at 85 K. Also, at higher incident angles, the proposed structure acts as a selective polarization-based filter without introducing any defect in the geometry.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1007/s13538-024-01485-z
Elizabeth Caroline Britto, Sagadevan K., Susan Christina Xavier, Sathish Kumar Danasegaran
Narrowband bandpass filters (BPFs) are in great need in future terahertz (THz) technologies to suppress EM signals beyond the operating band. THz filters and antennas play a crucial role in controlling and transmitting THz signals for the application of high data rate (6G) communication, non-destructive sensing, imaging, switching, and filtering. The proposed filtenna is designed using a dual-band THz BPF with a complementary split ring resonator (CSRR) metamaterial (MM). This paper suggests the circle in the pentagon (CP) filtenna and the simulation results show the filtering characteristics of two pass bands with resonant frequency (fr) between 6.3 and 7 THz and between 8 and 9.8 THz with a squared ratio of 0.54. Also, the maximum 3-dB bandwidth (BW) of 1.3 THz, low return loss (RL) of −28.46 dB, and low insertion loss (IL) of almost 0 were attained. The proposed antenna radiates at the frequency of 6.8 THz with an RL of −27.72 dB. The proposed CP filtenna applies to various wireless communication, especially in drone-to-drone communication with excellent data rates.
{"title":"Design of Narrowband Terahertz Filtenna for High-Speed Wireless Communication","authors":"Elizabeth Caroline Britto, Sagadevan K., Susan Christina Xavier, Sathish Kumar Danasegaran","doi":"10.1007/s13538-024-01485-z","DOIUrl":"https://doi.org/10.1007/s13538-024-01485-z","url":null,"abstract":"<p>Narrowband bandpass filters (BPFs) are in great need in future terahertz (THz) technologies to suppress EM signals beyond the operating band. THz filters and antennas play a crucial role in controlling and transmitting THz signals for the application of high data rate (6G) communication, non-destructive sensing, imaging, switching, and filtering. The proposed filtenna is designed using a dual-band THz BPF with a complementary split ring resonator (CSRR) metamaterial (MM). This paper suggests the circle in the pentagon (CP) filtenna and the simulation results show the filtering characteristics of two pass bands with resonant frequency (<i>f</i><sub><i>r</i></sub>) between 6.3 and 7 THz and between 8 and 9.8 THz with a squared ratio of 0.54. Also, the maximum 3-dB bandwidth (BW) of 1.3 THz, low return loss (RL) of −28.46 dB, and low insertion loss (IL) of almost 0 were attained. The proposed antenna radiates at the frequency of 6.8 THz with an RL of −27.72 dB. The proposed CP filtenna applies to various wireless communication, especially in drone-to-drone communication with excellent data rates.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1007/s13538-024-01489-9
Temesgen Kassaw
The investigation of plasma waves and instabilities in the context of relativistic, anisotropic drifting astrophysical plasma is the focus of this study. Utilizing fluid equations in the linear regime, the research reveals the emergence of novel instabilities as a result of drift velocity. Furthermore, the study uncovers a modification in the condition for the mirror instability due to the drift velocity. These findings potentially hold significant implications for comprehending plasma behavior in space environments, particularly in regions like the solar wind or the interstellar medium. The study proposes the further development of the theory to directly apply to space plasma, which could enhance our understanding of the intricate astrophysical systems that are driven by plasma dynamics.
{"title":"Waves and Instabilities in Relativistic, Anisotropic Drifting Astrophysical Plasma","authors":"Temesgen Kassaw","doi":"10.1007/s13538-024-01489-9","DOIUrl":"https://doi.org/10.1007/s13538-024-01489-9","url":null,"abstract":"<p>The investigation of plasma waves and instabilities in the context of relativistic, anisotropic drifting astrophysical plasma is the focus of this study. Utilizing fluid equations in the linear regime, the research reveals the emergence of novel instabilities as a result of drift velocity. Furthermore, the study uncovers a modification in the condition for the mirror instability due to the drift velocity. These findings potentially hold significant implications for comprehending plasma behavior in space environments, particularly in regions like the solar wind or the interstellar medium. The study proposes the further development of the theory to directly apply to space plasma, which could enhance our understanding of the intricate astrophysical systems that are driven by plasma dynamics.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-08DOI: 10.1007/s13538-024-01488-w
Horatiu Nastase, Caio Luiz Tiedt
In this note, we calculate susceptibilities, as derivatives of a thermodynamical potential, for the general perturbative holographic setup for transport with magnetic field, charge density and topological term, and compare with the quantities obtained in the standard (AdS_4) dyonic black hole analysis of Hartnoll and Kovtun. We find that the results do not match, despite previous expectations.
{"title":"Susceptibilities from Holographic Transport with Topological Term","authors":"Horatiu Nastase, Caio Luiz Tiedt","doi":"10.1007/s13538-024-01488-w","DOIUrl":"https://doi.org/10.1007/s13538-024-01488-w","url":null,"abstract":"<p>In this note, we calculate susceptibilities, as derivatives of a thermodynamical potential, for the general perturbative holographic setup for transport with magnetic field, charge density and topological term, and compare with the quantities obtained in the standard <span>(AdS_4)</span> dyonic black hole analysis of Hartnoll and Kovtun. We find that the results do not match, despite previous expectations.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1007/s13538-024-01473-3
Usuf Rahaman, M. Ikram, Ishfaq A. Rather, Anisul Ain Usmani
The present study focuses on investigating the shape evolution of neutron-rich even-even osmium (Os) transitional nuclei within the range of neutron number N = 82 to N = 190. The investigation is conducted using density-dependent meson-nucleon and point-coupling models within the framework of the covariant density functional theory (CDFT). Additionally, the results obtained from the CDFT calculations are compared with those obtained using the relativistic mean-field model with a nonlinear meson-nucleon interaction. The potential energy curve for Os isotopes (ranging from (^{158})Os to (^{260})Os) is analyzed in order to identify phase shape transitions, such as oblate-spherical-prolate. Furthermore, ground state bulk properties are calculated to gain insights into the structure of Os isotopes. The self-consistent calculations reveal a clear shape transition in the even-even Os isotopes, and overall, good agreement is observed among the different models employed as well as with the available experimental data.
本研究的重点是在中子数 N = 82 到 N = 190 的范围内研究富中子偶偶锇(Os)过渡核的形状演变。研究采用了协变密度泛函理论(CDFT)框架内的密度依赖介子-核子模型和点耦合模型。此外,还将 CDFT 计算得出的结果与使用具有非线性介子-核子相互作用的相对论均场模型得出的结果进行了比较。分析了 Os 同位素(从 (^{158})Os 到 (^{260})Os )的势能曲线,以确定相形转变,如扁圆形-球形-柱状。此外,还计算了基态块体性质,以深入了解 Os 同位素的结构。自洽计算揭示了偶偶数 Os 同位素中明显的形状转变,总体而言,所采用的不同模型之间以及与现有实验数据之间都具有良好的一致性。
{"title":"Microscopic Investigation of Ground State Properties and Shape Evolution in Osmium Isotopes","authors":"Usuf Rahaman, M. Ikram, Ishfaq A. Rather, Anisul Ain Usmani","doi":"10.1007/s13538-024-01473-3","DOIUrl":"https://doi.org/10.1007/s13538-024-01473-3","url":null,"abstract":"<p>The present study focuses on investigating the shape evolution of neutron-rich even-even osmium (Os) transitional nuclei within the range of neutron number N = 82 to N = 190. The investigation is conducted using density-dependent meson-nucleon and point-coupling models within the framework of the covariant density functional theory (CDFT). Additionally, the results obtained from the CDFT calculations are compared with those obtained using the relativistic mean-field model with a nonlinear meson-nucleon interaction. The potential energy curve for Os isotopes (ranging from <span>(^{158})</span>Os to <span>(^{260})</span>Os) is analyzed in order to identify phase shape transitions, such as oblate-spherical-prolate. Furthermore, ground state bulk properties are calculated to gain insights into the structure of Os isotopes. The self-consistent calculations reveal a clear shape transition in the even-even Os isotopes, and overall, good agreement is observed among the different models employed as well as with the available experimental data.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140885772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-06DOI: 10.1007/s13538-024-01482-2
Sonia Hatsue Tatumi, Matheus Toshio Mathias, René Rojas Rocca
The present study aimed to investigate pure lithium tetraborate (LTB) and silver (0.2%) doped LTB obtained via the solid-state route. XRD results revealed that the pure sample consisted of LTB crystals, while doped samples comprised lithium tetraborate (Li2B4O7), lithium triborate (LiB3O5), and Li2B4O4, with an average crystallite size of about (40 ± 2) nm. TL (UV-VIS) analysis of LTB exhibited a peak at 125 °C, while doped samples supplied additional peaks at 205 °C, 315 °C, and 380 °C. LTB showed TL (UV) peaks at 120 °C and 210 °C, whereas doped samples exhibited peaks at 120 °C, 180 °C, and 295 °C. The TL response demonstrated a linear increase within the 0.081 to 5 Gy dose interval. Experimental TL glow curves could be fitted using a general order kinetics (GOK) model. TL emission spectra of LTB revealed bands at 330 nm and 580 nm, while LTB:Ag exhibited bands at 280 nm, 300 nm, and 584 nm. The presence of Ag substantially increased the TL intensity and introduced new peaks at high temperatures.
{"title":"Effect of Ag Doping on Crystallography and TL Emissions of $${{text{Li}}}_{2}{text{O}}{,-,{text{B}}}_{2}{{text{O}}}_{3}$$ System","authors":"Sonia Hatsue Tatumi, Matheus Toshio Mathias, René Rojas Rocca","doi":"10.1007/s13538-024-01482-2","DOIUrl":"https://doi.org/10.1007/s13538-024-01482-2","url":null,"abstract":"<p>The present study aimed to investigate pure lithium tetraborate (LTB) and silver (0.2%) doped LTB obtained via the solid-state route. XRD results revealed that the pure sample consisted of LTB crystals, while doped samples comprised lithium tetraborate (Li<sub>2</sub>B<sub>4</sub>O<sub>7</sub>), lithium triborate (LiB<sub>3</sub>O<sub>5</sub>), and Li<sub>2</sub>B<sub>4</sub>O<sub>4</sub>, with an average crystallite size of about (40 ± 2) nm. TL (UV-VIS) analysis of LTB exhibited a peak at 125 °C, while doped samples supplied additional peaks at 205 °C, 315 °C, and 380 °C. LTB showed TL (UV) peaks at 120 °C and 210 °C, whereas doped samples exhibited peaks at 120 °C, 180 °C, and 295 °C. The TL response demonstrated a linear increase within the 0.081 to 5 Gy dose interval. Experimental TL glow curves could be fitted using a general order kinetics (GOK) model. TL emission spectra of LTB revealed bands at 330 nm and 580 nm, while LTB:Ag exhibited bands at 280 nm, 300 nm, and 584 nm. The presence of Ag substantially increased the TL intensity and introduced new peaks at high temperatures.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140885846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-04DOI: 10.1007/s13538-024-01465-3
P. ShunmugaSundaram, R. Shanmugam, A. Elangovan, L. Bruno Chandrasekhar, K. Gurushankar, G. Arivazhagan
Intrinsic and chromium (Cr) doped zinc sulfide (ZnS) nanoparticles (NPs) have been synthesized by the co-precipitation method. The X-ray diffraction (XRD) studies reveals that the nanoparticles are crystalline in nature with cubic phase that have the (111) as preferential orientation. Even though the Cr ions have ionic radii greater than Zn, no significant modification in the crystal structure occurs as revealed by the XRD pattern. The doping induces a reduction in the peak intensities. The optical energy band gap values decrease and the Urbach exponential tail width increases with an increase in Cr level. When the dopant concentration is increased, the microstrain decreases and crystallite size increases. The surface morphology analysis has been carried out using scanning electron microscopy (SEM). The presence of the elements Zn, S, and Cr has been conformed using energy-dispersive X-ray spectroscopy (EDAX). The intensity that corresponds to Cr lines increases as the dopant increases with respect to Zn which is an evidence of the increased Cr level.
通过共沉淀法合成了本征和掺杂铬(Cr)的硫化锌(ZnS)纳米粒子(NPs)。X 射线衍射(XRD)研究表明,这些纳米粒子呈晶体状,立方相的优先取向为 (111)。尽管铬离子的离子半径大于锌离子,但从 X 射线衍射图谱上看,晶体结构并没有发生明显变化。掺杂导致峰强度降低。随着铬含量的增加,光能带隙值减小,Urbach 指数尾宽增大。当掺杂浓度增加时,微应变减小,晶粒尺寸增大。使用扫描电子显微镜(SEM)进行了表面形貌分析。利用能量色散 X 射线光谱(EDAX)分析了 Zn、S 和 Cr 元素的存在。与 Zn 相比,随着掺杂量的增加,与 Cr 线相对应的强度也在增加,这证明了 Cr 含量的增加。
{"title":"Structural and Optical Studies on Cr-Doped ZnS Nanoparticles Prepared by Flat Co-precipitation Method","authors":"P. ShunmugaSundaram, R. Shanmugam, A. Elangovan, L. Bruno Chandrasekhar, K. Gurushankar, G. Arivazhagan","doi":"10.1007/s13538-024-01465-3","DOIUrl":"https://doi.org/10.1007/s13538-024-01465-3","url":null,"abstract":"<p>Intrinsic and chromium (Cr) doped zinc sulfide (ZnS) nanoparticles (NPs) have been synthesized by the co-precipitation method. The X-ray diffraction (XRD) studies reveals that the nanoparticles are crystalline in nature with cubic phase that have the (111) as preferential orientation. Even though the Cr ions have ionic radii greater than Zn, no significant modification in the crystal structure occurs as revealed by the XRD pattern. The doping induces a reduction in the peak intensities. The optical energy band gap values decrease and the Urbach exponential tail width increases with an increase in Cr level. When the dopant concentration is increased, the microstrain decreases and crystallite size increases. The surface morphology analysis has been carried out using scanning electron microscopy (SEM). The presence of the elements Zn, S, and Cr has been conformed using energy-dispersive X-ray spectroscopy (EDAX). The intensity that corresponds to Cr lines increases as the dopant increases with respect to Zn which is an evidence of the increased Cr level.</p>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140885770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}