Pub Date : 2024-10-05DOI: 10.1016/j.cap.2024.10.002
Hyungwoo Lee , Minae Ouk , Inseo Kim , Biyi Kim , Seok Bae , Sungwon David Roh , Isao Tanaka , Minseok Choi
Using first-principles calculation based on density-functional theory and density-functional perturbation theory, the microscopic structure and dielectric properties of Lanthanide (Ln) doped BaTiO3 are investigated. The doped Ln atoms exhibit significant displacement from Ba sites for charge compensation, forming off-centered configurations. This displacement is more pronounced for elements with smaller ionic radii. The change in ionic dielectric constant is strongly correlated with Ln displacement and Ln ion radius. As Ln displacement (ionic radius) increases (decreases), Ln-doped BaTiO3 has a higher ionic dielectric constant. However, regardless of the Ln species, the added Ln reduces the ionic dielectric constant compared to pristine BaTiO3.
{"title":"First-principles study on lanthanide dopants in BaTiO3","authors":"Hyungwoo Lee , Minae Ouk , Inseo Kim , Biyi Kim , Seok Bae , Sungwon David Roh , Isao Tanaka , Minseok Choi","doi":"10.1016/j.cap.2024.10.002","DOIUrl":"10.1016/j.cap.2024.10.002","url":null,"abstract":"<div><div>Using first-principles calculation based on density-functional theory and density-functional perturbation theory, the microscopic structure and dielectric properties of Lanthanide (Ln) doped BaTiO<sub>3</sub> are investigated. The doped Ln atoms exhibit significant displacement from Ba sites for charge compensation, forming off-centered configurations. This displacement is more pronounced for elements with smaller ionic radii. The change in ionic dielectric constant is strongly correlated with Ln displacement and Ln ion radius. As Ln displacement (ionic radius) increases (decreases), Ln-doped BaTiO<sub>3</sub> has a higher ionic dielectric constant. However, regardless of the Ln species, the added Ln reduces the ionic dielectric constant compared to pristine BaTiO<sub>3</sub>.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 238-241"},"PeriodicalIF":2.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432076","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 : 2024-10-04DOI: 10.1016/j.cap.2024.10.004
Dimitar N. Petrov , J. Ćwik , H.N. Nhat , D.-H. Kim , T.L. Phan
In this paper, we discuss the magnetic behavior and magnetocaloric effect of lithium erbium tetraphosphate (LiErP4O12) single crystal in the temperature range 2–85 K under magnetic fields up to 50 kOe. Detailed investigation of the temperature-dependent magnetization M(T) proves an existence of magnetic ordering below Tm, which has been estimated as a minimum in the dM/dT vs. T dependence. Above Tm, LiErP4O12 possesses paramagnetic behavior and its magnetic susceptibility follows the Curie-Weiss law giving a higher value of the effective magnetic moment of Er3+ compared to the theoretical one. This could be due to the Kramers spin degeneracy and the Stark structure of multiplets. Under an applied field H = 50 kOe, the maximum value of the magnetic-entropy change at 2 K reaches about 15 J/kgK, corresponding to a relative-cooling-power value of ∼343 J/kg. Assessments of the magnetic ordering exponent n and N(T, H) data prove LiErP4O12 exhibiting short-range magnetic order. Due to the absence of magnetic hysteresis and large magnetocaloric response, we believe that LiErP4O12 could be a promising candidate for magnetic-cooling applications in liquefying hydrogen and 3He isotope.
本文讨论了四磷酸铒锂（LiErP4O12）单晶体在磁场高达 50 kOe 的情况下，在 2-85 K 温度范围内的磁性行为和磁致效应。对随温度变化的磁化 M(T) 的详细研究证明，在低于 Tm 时存在磁有序性，这被估计为 dM/dT 与 T 的关系中的最小值。高于 Tm 时，LiErP4O12 具有顺磁性，其磁感应强度遵循居里-韦斯定律，与理论值相比，Er3+ 的有效磁矩值更高。这可能是由于克拉默自旋退化和多子的斯塔克结构造成的。在外加磁场 H = 50 kOe 的条件下，2 K 时的磁熵变化最大值约为 15 J/kgK，对应的相对冷却功率值为 ∼343 J/kg。磁有序指数 n 和 N（T，H）数据的评估证明 LiErP4O12 具有短程磁有序性。由于LiErP4O12不存在磁滞和较大的磁热反应，我们认为它有希望成为液化氢和3He同位素的磁制冷应用的候选材料。
{"title":"Magnetocaloric effect of LiErP4O12 single crystal exhibiting competing ferromagnetic and anti-ferromagnetic interactions","authors":"Dimitar N. Petrov , J. Ćwik , H.N. Nhat , D.-H. Kim , T.L. Phan","doi":"10.1016/j.cap.2024.10.004","DOIUrl":"10.1016/j.cap.2024.10.004","url":null,"abstract":"<div><div>In this paper, we discuss the magnetic behavior and magnetocaloric effect of lithium erbium tetraphosphate (LiErP<sub>4</sub>O<sub>12</sub>) single crystal in the temperature range 2–85 K under magnetic fields up to 50 kOe. Detailed investigation of the temperature-dependent magnetization <em>M</em>(<em>T</em>) proves an existence of magnetic ordering below <em>T</em><sub><em>m</em></sub>, which has been estimated as a minimum in the <em>dM</em>/<em>dT vs</em>. <em>T</em> dependence. Above <em>T</em><sub><em>m</em></sub>, LiErP<sub>4</sub>O<sub>12</sub> possesses paramagnetic behavior and its magnetic susceptibility follows the Curie-Weiss law giving a higher value of the effective magnetic moment of Er<sup>3+</sup> compared to the theoretical one. This could be due to the Kramers spin degeneracy and the Stark structure of multiplets. Under an applied field <em>H</em> = 50 kOe, the maximum value of the magnetic-entropy change at 2 K reaches about 15 J/kgK, corresponding to a relative-cooling-power value of ∼343 J/kg. Assessments of the magnetic ordering exponent <em>n</em> and <em>N</em>(<em>T</em>, <em>H</em>) data prove LiErP<sub>4</sub>O<sub>12</sub> exhibiting short-range magnetic order. Due to the absence of magnetic hysteresis and large magnetocaloric response, we believe that LiErP<sub>4</sub>O<sub>12</sub> could be a promising candidate for magnetic-cooling applications in liquefying hydrogen and <sup>3</sup>He isotope.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 224-229"},"PeriodicalIF":2.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427498","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 : 2024-10-02DOI: 10.1016/j.cap.2024.09.013
G.Sh. Boltachev, P.A. Russkikh, S.A. Chaikovsky
The heat release that occurs in a cylindrical conductor carrying an alternating current is analyzed for the cases when the conductor has axisymmetric surface irregularities of one of three types: local bumps, local pits, and sequences of alternating bumps and pits (wavy irregularities). The magnetic field and current density distributions over the conductor cross section have been simulated. The simulation parameters were chosen to match the conditions of experiments on the generation of strong magnetic fields. However, due to the analysis of the initial heating stage, the problem is solved neglecting the temperature dependence of the resistivity of the material. A multiple increase in heat release power in the vicinity of a surface irregularity has been revealed for the three types of irregularities.
{"title":"Enhanced Joule heat release at surface irregularities","authors":"G.Sh. Boltachev, P.A. Russkikh, S.A. Chaikovsky","doi":"10.1016/j.cap.2024.09.013","DOIUrl":"10.1016/j.cap.2024.09.013","url":null,"abstract":"<div><div>The heat release that occurs in a cylindrical conductor carrying an alternating current is analyzed for the cases when the conductor has axisymmetric surface irregularities of one of three types: local bumps, local pits, and sequences of alternating bumps and pits (wavy irregularities). The magnetic field and current density distributions over the conductor cross section have been simulated. The simulation parameters were chosen to match the conditions of experiments on the generation of strong magnetic fields. However, due to the analysis of the initial heating stage, the problem is solved neglecting the temperature dependence of the resistivity of the material. A multiple increase in heat release power in the vicinity of a surface irregularity has been revealed for the three types of irregularities.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 189-195"},"PeriodicalIF":2.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427491","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 : 2024-09-27DOI: 10.1016/j.cap.2024.09.012
Aman Kumar, Richa Sharma
A flexible piezoelectric energy harvesting device was manufactured using Mn-doped ZnO (MnZ)/poly (vinylidene fluoride) (PVDF) composite film of various proportions of MnZ particles (5 wt%, 10 wt%, 20 wt% and 30 wt%) within the PVDF matrix. The phase formation, crystallinity and morphological characteristics of the fabricated composite films were analysed with the help of Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The piezoelectric performance of the constructed piezoelectric generator (PEG) device was measured by applying force on its surface which produced a significantly high open-circuit voltage of 344V and power density of 4.53 mW/cm2. Besides, these lead-free composite devices demonstrated remarkable sensitivity for human body motion detection in punching, finger bending, and wrist bending. Furthermore, practical usage of the fabricated PEG device was shown by powering devices like wristwatches, digital thermometers and glowing 20 light-emitting diodes (LEDs) of different colours.
{"title":"Piezoelectric flexible generator based on Mn-doped ZnO/PVDF composite films for energy harvesting application","authors":"Aman Kumar, Richa Sharma","doi":"10.1016/j.cap.2024.09.012","DOIUrl":"10.1016/j.cap.2024.09.012","url":null,"abstract":"<div><div>A flexible piezoelectric energy harvesting device was manufactured using Mn-doped ZnO (MnZ)/poly (vinylidene fluoride) (PVDF) composite film of various proportions of MnZ particles (5 wt%, 10 wt%, 20 wt% and 30 wt%) within the PVDF matrix. The phase formation, crystallinity and morphological characteristics of the fabricated composite films were analysed with the help of Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The piezoelectric performance of the constructed piezoelectric generator (PEG) device was measured by applying force on its surface which produced a significantly high open-circuit voltage of 344V and power density of 4.53 mW/cm<sup>2</sup>. Besides, these lead-free composite devices demonstrated remarkable sensitivity for human body motion detection in punching, finger bending, and wrist bending. Furthermore, practical usage of the fabricated PEG device was shown by powering devices like wristwatches, digital thermometers and glowing 20 light-emitting diodes (LEDs) of different colours.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 159-168"},"PeriodicalIF":2.4,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358583","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 : 2024-09-27DOI: 10.1016/j.cap.2024.09.010
Jonggu Han , Jihoon Kim , Woojin Park , Sang Jun Park , Song Yi Baek , Byeongsun Yoo , Chulhwan Choi , Se Youn Moon
Although magnetized plasmas have been frequently used to enhance the process rate or improve the film quality via the control of ion flux as well as energy and plasma density in semiconductor processes, the inhomogeneous magnetic field—which leads to plasma non-uniformity—remains as a problem to be solved. To address this problem, it is essential to conduct a comprehensive assessment of the magnetic effect throughout the entire discharge. Therefore, in the present study, we investigated the magnetic field effects (B < 100 G) on a capacitively-coupled nitrogen plasma based on spectroscopic analyses. The spatially-resolved emission spectra were measured along the radial direction at various vertical positions under the pressures of 10 mTorr and 250 mTorr both with and without magnetic field. By analyzing emission spectra such as N2 FPS, N2 SPS, N2+ FNS, and N I, we were able to obtain the radial distributions of reactive species density, vibrational temperature, and excitation temperature. In low-pressure plasma, with the application of a magnetic field, maximum increases in vibrational temperature and excitation temperature of 462 K and 491 K, respectively, were observed within the bulk region beneath the magnet. This magnetic effect resulted in a significant increase in reactive species density along the radial direction. It was also found that the local enhancement of ion density by magnetic field was strongly related to the increase in excitation temperature and the density of the N2+(B) state. From this result, it is suggested that introducing an asymmetric magnetic field could modulate the spatial distributions of the physical and chemical properties of the plasma.
虽然磁化等离子体已被广泛用于半导体工艺中，通过控制离子流量、能量和等离子体密度来提高工艺速率或改善薄膜质量，但导致等离子体不均匀的不均匀磁场仍然是一个有待解决的问题。要解决这个问题，必须对整个放电过程中的磁效应进行全面评估。因此，在本研究中，我们基于光谱分析研究了磁场效应（B < 100 G）对电容耦合氮等离子体的影响。在有磁场和无磁场的 10 mTorr 和 250 mTorr 压力下，沿径向在不同垂直位置测量了空间分辨发射光谱。通过分析 N2 FPS、N2 SPS、N2+ FNS 和 N I 等发射光谱，我们获得了反应物密度、振动温度和激发温度的径向分布。在低压等离子体中，施加磁场后，在磁体下方的体积区域内观察到振动温度和激发温度的最大升高分别为 462 K 和 491 K。这种磁效应导致反应物密度沿径向显著增加。研究还发现，磁场对离子密度的局部增强与激发温度和 N2+(B)态密度的增加密切相关。这一结果表明，引入不对称磁场可以调节等离子体物理和化学特性的空间分布。
{"title":"Spatially-resolved spectroscopic investigation of the inhomogeneous magnetic field effects on a low-pressure capacitively-coupled nitrogen plasma","authors":"Jonggu Han , Jihoon Kim , Woojin Park , Sang Jun Park , Song Yi Baek , Byeongsun Yoo , Chulhwan Choi , Se Youn Moon","doi":"10.1016/j.cap.2024.09.010","DOIUrl":"10.1016/j.cap.2024.09.010","url":null,"abstract":"<div><div>Although magnetized plasmas have been frequently used to enhance the process rate or improve the film quality via the control of ion flux as well as energy and plasma density in semiconductor processes, the inhomogeneous magnetic field—which leads to plasma non-uniformity—remains as a problem to be solved. To address this problem, it is essential to conduct a comprehensive assessment of the magnetic effect throughout the entire discharge. Therefore, in the present study, we investigated the magnetic field effects (B < 100 G) on a capacitively-coupled nitrogen plasma based on spectroscopic analyses. The spatially-resolved emission spectra were measured along the radial direction at various vertical positions under the pressures of 10 mTorr and 250 mTorr both with and without magnetic field. By analyzing emission spectra such as N<sub>2</sub> FPS, N<sub>2</sub> SPS, N<sub>2</sub><sup>+</sup> FNS, and N I, we were able to obtain the radial distributions of reactive species density, vibrational temperature, and excitation temperature. In low-pressure plasma, with the application of a magnetic field, maximum increases in vibrational temperature and excitation temperature of 462 K and 491 K, respectively, were observed within the bulk region beneath the magnet. This magnetic effect resulted in a significant increase in reactive species density along the radial direction. It was also found that the local enhancement of ion density by magnetic field was strongly related to the increase in excitation temperature and the density of the N<sub>2</sub><sup>+</sup>(B) state. From this result, it is suggested that introducing an asymmetric magnetic field could modulate the spatial distributions of the physical and chemical properties of the plasma.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 180-188"},"PeriodicalIF":2.4,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427490","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 : 2024-09-26DOI: 10.1016/j.cap.2024.09.011
Rahul Kumar Yadav, Neha Bisht, Parag R. Patil, Ho Jae Ki, Sang Won Lee, Yong Tae Kim, Pravin S. Pawar, Indu Sharma, Vishesh Manjunath, Jaeyeong Heo
Herein, we present the simulation (using the SCAPS-1D program), of a bilayer absorber solar cell. First, we numerically studied the bilayer model using our experimentally observed parameters and investigated the results. The results from the bilayer absorber (SnSe/SnS) numerical analysis were then compared with a single (SnS and SnSe) absorber modeling. The optimized device with a bilayer absorber exhibited the highest performance, with a photo conversion efficiency (PCE) of 22.35%. In comparison, the single SnS and SnSe absorbers achieved a PCE of 14.79% and 13.69%. Furthermore, we compared this numerical study with our previous study having the same configuration. Although there was a significant difference in performance between the simulated and experimental studies, the outcomes of the fabricated devices exhibited similar trends to the simulations. Finally, we attempted to determine the key parameters responsible for the reduced performance in the experimental study.
{"title":"A comprehensive numerical study of bilayer SnSe/SnS absorber based solar cells","authors":"Rahul Kumar Yadav, Neha Bisht, Parag R. Patil, Ho Jae Ki, Sang Won Lee, Yong Tae Kim, Pravin S. Pawar, Indu Sharma, Vishesh Manjunath, Jaeyeong Heo","doi":"10.1016/j.cap.2024.09.011","DOIUrl":"10.1016/j.cap.2024.09.011","url":null,"abstract":"<div><div>Herein, we present the simulation (using the SCAPS-1D program), of a bilayer absorber solar cell. First, we numerically studied the bilayer model using our experimentally observed parameters and investigated the results. The results from the bilayer absorber (SnSe/SnS) numerical analysis were then compared with a single (SnS and SnSe) absorber modeling. The optimized device with a bilayer absorber exhibited the highest performance, with a photo conversion efficiency (PCE) of 22.35%. In comparison, the single SnS and SnSe absorbers achieved a PCE of 14.79% and 13.69%. Furthermore, we compared this numerical study with our previous study having the same configuration. Although there was a significant difference in performance between the simulated and experimental studies, the outcomes of the fabricated devices exhibited similar trends to the simulations. Finally, we attempted to determine the key parameters responsible for the reduced performance in the experimental study.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 169-179"},"PeriodicalIF":2.4,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358584","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}
First-principles calculations are employed to investigate the interfacial properties on the Zr-doped sulfide solid electrolytes. Theoretical calculation results show that the PS4 tetrahedral structure near the Li/Li3PS4 interface is severely damaged, whereas the Zr-doped sulfide solid electrolyte interface structure has a slight deformation. The Li ions migration energy barrier on the Zr-doped sulfide solid electrolyte interface is relatively lower than that on the Li/Li3PS4. Moreover, the stress-strain analysis indicates that the Li/Li3PS4 interface structure experiences a maximum strain of only 6 %, while the Zr-doped sulfide solid electrolyte interface structure experiences a maximum strain of 10 %. This may be attributed to the ability of Zr doping to prevent S2− diffusion into the lithium metal anode and stabilize the Li ion transport skeleton. Therefore, Zr doping can improve the interface structure stability. This study will provide a useful perspective for designing high performance of solid electrolytes for the application of all-solid-state batteries.
{"title":"Exploring interfacial stability for Zr-doped sulfide solid electrolyte with first-principle calculation","authors":"Junbo Zhang , Wenjin Gong , Nini Qian , Bingbing Chen , Jianqiu Zhou","doi":"10.1016/j.cap.2024.09.009","DOIUrl":"10.1016/j.cap.2024.09.009","url":null,"abstract":"<div><div>First-principles calculations are employed to investigate the interfacial properties on the Zr-doped sulfide solid electrolytes. Theoretical calculation results show that the PS<sub>4</sub> tetrahedral structure near the Li/Li<sub>3</sub>PS<sub>4</sub> interface is severely damaged, whereas the Zr-doped sulfide solid electrolyte interface structure has a slight deformation. The Li ions migration energy barrier on the Zr-doped sulfide solid electrolyte interface is relatively lower than that on the Li/Li<sub>3</sub>PS<sub>4</sub>. Moreover, the stress-strain analysis indicates that the Li/Li<sub>3</sub>PS<sub>4</sub> interface structure experiences a maximum strain of only 6 %, while the Zr-doped sulfide solid electrolyte interface structure experiences a maximum strain of 10 %. This may be attributed to the ability of Zr doping to prevent S<sup>2−</sup> diffusion into the lithium metal anode and stabilize the Li ion transport skeleton. Therefore, Zr doping can improve the interface structure stability. This study will provide a useful perspective for designing high performance of solid electrolytes for the application of all-solid-state batteries.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 144-150"},"PeriodicalIF":2.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327949","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 : 2024-09-24DOI: 10.1016/j.cap.2024.09.008
Asha Rani , Rajesh Parmar , R.S. Kundu
Specifically, the study looks into dielectric characteristics () and complex modulus formulation and AC conductivity of lead-modified bismuth borovanadate glasses (50-x) V2O5-40 B2O3-10 Bi2O3-xPbO, where x = 5,10, 15, 20 and 25 mol% with sample ID's VPb1, VPb2, VPb3, VPb4 & VPb5 according to different compositions of lead and vanadate. When the PbO content rises, there is a decreasing tendency in both the alternating current conductivity and dielectric constants. In order to fit AC conductivity data, Almond West equation is used to extract parameters, including crossover frequency (), frequency exponent (s), and direct current conductivity (. Direct current conduction mechanism in all glass samples except VPb5 [Correlated Barriers Hopping (CBH) conduction at all frequencies] at lower frequencies might potentially be attributed to large-polaron quantum mechanical tunneling (LQMT). Similar to this, at high frequencies, small polaron quantum mechanical tunnelling is followed by VPb2 & VPb3 while LQMT is followed by VPb1 & VPb4. Activation energy of dc conduction () at higher frequencies (0.373–0.476 eV) for samples having sample ID VPb1 to VPb4 and sample VPb5 at all frequencies with 0.686 eV and modulus activation energy (0.382–0.534 eV) are found in good agreement. Dielectric studies reveal non-Debye-type behaviour.
具体来说，该研究考察了铅改性硼钒酸铋玻璃（50-x）V2O5-40 B2O3-10 Bi2O3-xPbO（其中 x = 5、10、15、20 和 25 mol%，样品 ID 为 VPb1、VPb2、VPb3、VPb4 & VPb5）的介电常数（ε′和ε″）、复合模量配方和交流电导率。当氧化铅含量增加时，交流电导率和介电常数都呈下降趋势。为了拟合交流导电率数据，使用了 Almond West 方程来提取参数，包括交叉频率 (ωH)、频率指数 (s) 和直流导电率 (σdc)。除了 VPb5 [所有频率下的相关势垒跳频 (CBH) 传导]之外，所有玻璃样品在较低频率下的直流传导机制都可能归因于大极子量子力学隧道 (LQMT)。与此类似，在高频率下，VPb2 & VPb3 跟着小极子量子机械隧道，而 VPb1 & VPb4 跟着 LQMT。样品 ID 为 VPb1 至 VPb4 的样品在较高频率下的直流传导活化能（Edc）（0.373-0.476 eV）与样品 VPb5 在所有频率下的 Edc 0.686 eV 和模量活化能（ER）（0.382-0.534 eV）非常一致。介电研究显示了非德拜型行为。
{"title":"Electrical characterization of lead-modified bismuth borovanadate glasses","authors":"Asha Rani , Rajesh Parmar , R.S. Kundu","doi":"10.1016/j.cap.2024.09.008","DOIUrl":"10.1016/j.cap.2024.09.008","url":null,"abstract":"<div><div>Specifically, the study looks into dielectric characteristics (<span><math><mrow><msup><mi>ε</mi><mo>′</mo></msup><mtext>and</mtext><mspace></mspace><msup><mi>ε</mi><mo>″</mo></msup></mrow></math></span>) and complex modulus formulation and AC conductivity of lead-modified bismuth borovanadate glasses (50-x) V<sub>2</sub>O<sub>5</sub>-40 B<sub>2</sub>O<sub>3</sub>-10 Bi<sub>2</sub>O<sub>3</sub>-xPbO, where x = 5,10, 15, 20 and 25 mol% with sample ID's VPb1, VPb2, VPb3, VPb4 & VPb5 according to different compositions of lead and vanadate. When the PbO content rises, there is a decreasing tendency in both the alternating current conductivity and dielectric constants. In order to fit AC conductivity data, Almond West equation is used to extract parameters, including crossover frequency (<span><math><mrow><msub><mi>ω</mi><mi>H</mi></msub></mrow></math></span>), frequency exponent (s), and direct current conductivity (<span><math><mrow><msub><mi>σ</mi><mrow><mi>d</mi><mi>c</mi></mrow></msub><mo>)</mo></mrow></math></span>. Direct current conduction mechanism in all glass samples except VPb5 [Correlated Barriers Hopping (CBH) conduction at all frequencies] at lower frequencies might potentially be attributed to large-polaron quantum mechanical tunneling (LQMT). Similar to this, at high frequencies, small polaron quantum mechanical tunnelling is followed by VPb2 & VPb3 while LQMT is followed by VPb1 & VPb4. Activation energy of dc conduction (<span><math><mrow><msub><mi>E</mi><mtext>dc</mtext></msub></mrow></math></span>) at higher frequencies (0.373–0.476 eV) for samples having sample ID VPb1 to VPb4 and sample VPb5 at all frequencies with <span><math><mrow><msub><mi>E</mi><mtext>dc</mtext></msub></mrow></math></span> 0.686 eV and modulus activation energy <span><math><mrow><mo>(</mo><msub><mi>E</mi><mi>R</mi></msub><mo>)</mo></mrow></math></span> (0.382–0.534 eV) are found in good agreement. Dielectric studies reveal non-Debye-type behaviour.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 151-158"},"PeriodicalIF":2.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358582","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 : 2024-09-12DOI: 10.1016/j.cap.2024.09.007
See-eun Tae , Ahmed Yousef Mohamed , Kosuke Kitase , Takafumi Kitazawa , Deok-Yong Cho
We investigated the compositional and temperature (T) dependences of vibrational frequencies in Hofmann-type Fe(L)2[M(CN)4] spin-crossover (SCO) coordination polymers in which {M = Ni, Pd or Pt with L = pyridine (py)}, or {L = 3-Cl-py or 3-methylpy with M = Ni}, using Raman spectroscopy. The SCO-driven peak shifts (in wavenumber) ranged up to ∼170 cm−1, manifesting significant spin-dependent structural evolutions. Furthermore, there appear clear HS signatures even at T ≪ TSCO for L = 3-Cl-py or 3-methylpy implying the steric effects of the organic ligands on the HS trapping. Meanwhile, for L = py, such HS trapping at the low temperature was not significant although some spectra taken under high laser fluence exhibit light-induced excited spin state trapping (LIESST) effect. The mechanism of the LIESST is discussed in detail in terms of the M d – C 2sp hybridization effects.
我们利用拉曼光谱研究了霍夫曼型 Fe(L)2[M(CN)4] 自旋交叉（SCO）配位聚合物（其中 {M = Ni、Pd 或 Pt，L = 吡啶 (py)} 或 {L = 3-Cl-py 或 3-甲基py，M = Ni}）振动频率的组成和温度（T）依赖性。SCO 驱动的峰值偏移（以波长表示）范围高达 ∼170 cm-1，显示出显著的自旋依赖性结构演变。此外，对于 L = 3-Cl-py 或 3-methylpy 来说，即使在 T≪ TSCO 时也会出现明显的 HS 信号，这意味着有机配体对 HS 捕获的立体效应。同时，对于 L = py，虽然在高激光通量下拍摄的一些光谱显示了光诱导激发自旋态捕获（LIESST）效应，但这种低温下的 HS 捕获并不显著。本文从 M d - C 2sp 杂化效应的角度详细讨论了 LIESST 的机理。
{"title":"Understanding spin-dependent vibrational frequencies in Fe(II) metal organic coordination complexes","authors":"See-eun Tae , Ahmed Yousef Mohamed , Kosuke Kitase , Takafumi Kitazawa , Deok-Yong Cho","doi":"10.1016/j.cap.2024.09.007","DOIUrl":"10.1016/j.cap.2024.09.007","url":null,"abstract":"<div><p>We investigated the compositional and temperature (<em>T</em>) dependences of vibrational frequencies in Hofmann-type Fe(<em>L</em>)<sub>2</sub>[<em>M</em>(CN)<sub>4</sub>] spin-crossover (SCO) coordination polymers in which {<em>M</em> = Ni, Pd or Pt with <em>L</em> = pyridine (py)}, or {<em>L</em> = 3-Cl-py or 3-methylpy with <em>M</em> = Ni}, using Raman spectroscopy. The SCO-driven peak shifts (in wavenumber) ranged up to ∼170 cm<sup>−1</sup>, manifesting significant spin-dependent structural evolutions. Furthermore, there appear clear HS signatures even at <em>T</em> ≪ <em>T</em><sub>SCO</sub> for <em>L</em> = 3-Cl-py or 3-methylpy implying the steric effects of the organic ligands on the HS trapping. Meanwhile, for <em>L</em> = py, such HS trapping at the low temperature was not significant although some spectra taken under high laser fluence exhibit light-induced excited spin state trapping (LIESST) effect. The mechanism of the LIESST is discussed in detail in terms of the <em>M</em> d – C 2sp hybridization effects.</p></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 138-143"},"PeriodicalIF":2.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243733","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 : 2024-09-11DOI: 10.1016/j.cap.2024.09.006
Hanwool Seong , Won-Young Choi , Jongbum Choi , Duck-Ho Kim , Tae-Eon Park , Byoung-Chul Min , Heon-Jin Choi , Dong-Soo Han
The unique properties of ferrimagnets including easy detection of their dynamic and static states, strong resistance to external disturbances, and rapid dynamic characteristics, have made them attractive in the spintronics community. Our study focuses on the engineering of these magnetic properties of ferrimagnets, particularly employing a GdFeCo alloy, a prominent ferrimagnetic material, by utilizing magnetron sputtering. A series of GdFeCo films are fabricated by altering their thicknesses and working pressure during the sputtering process. Our experimental results reveal that these sputtering parameters significantly influence a Gd composition within the films, which in turn affects critical properties of ferrimagnets such as magnetic anisotropy, and magnetic moment compensation temperature. By precisely controlling these sputtering parameters, we successfully tailored the magnetic properties of the GdFeCo thin films with desired properties, offering new possibilities for the creation of sophisticated magnetic materials tailored to specific technological needs.
{"title":"Magnetic properties of GdFeCo thin films tailored by sputtering conditions","authors":"Hanwool Seong , Won-Young Choi , Jongbum Choi , Duck-Ho Kim , Tae-Eon Park , Byoung-Chul Min , Heon-Jin Choi , Dong-Soo Han","doi":"10.1016/j.cap.2024.09.006","DOIUrl":"10.1016/j.cap.2024.09.006","url":null,"abstract":"<div><p>The unique properties of ferrimagnets including easy detection of their dynamic and static states, strong resistance to external disturbances, and rapid dynamic characteristics, have made them attractive in the spintronics community. Our study focuses on the engineering of these magnetic properties of ferrimagnets, particularly employing a GdFeCo alloy, a prominent ferrimagnetic material, by utilizing magnetron sputtering. A series of GdFeCo films are fabricated by altering their thicknesses and working pressure during the sputtering process. Our experimental results reveal that these sputtering parameters significantly influence a Gd composition within the films, which in turn affects critical properties of ferrimagnets such as magnetic anisotropy, and magnetic moment compensation temperature. By precisely controlling these sputtering parameters, we successfully tailored the magnetic properties of the GdFeCo thin films with desired properties, offering new possibilities for the creation of sophisticated magnetic materials tailored to specific technological needs.</p></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"68 ","pages":"Pages 131-137"},"PeriodicalIF":2.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227941","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号