Pub Date : 2024-10-11DOI: 10.1016/j.physb.2024.416598
In this paper, we numerically study the transport properties of a resonant tunneling diode (RTD) based on graphene nanoribbon (GNR) with an H-type antidote between the contacts. The structure may also be thought of as having two parallel (W-shape) parts connecting the contacts, each having a wider channel region sandwiched between two narrower barrier regions. The energy at which quasi-bound states occur in each part depends on the dimensional parameters of the respective portion in the structure. We study how the transmission through quasi-bound states is influenced by the edge states on the contacts and dimensional parameters such as barrier length and also by the ambient temperature. The results are compared with those of an RTD with a single part connecting the contacts. Transmission peaks at different energies are observed for an RTD with asymmetrical lower and upper parts between the contacts. This is then utilized for the creation of two negative differential resistance (NDR) peaks. For numerical computation, the non-equilibrium Green’s function formalism (NEGF) based on the nearest neighbor tight-binding model is employed.
本文对基于石墨烯纳米带（GNR）的共振隧穿二极管（RTD）的传输特性进行了数值研究，该器件的触点之间具有 H 型解毒剂。这种结构也可以看作是连接触点的两个平行（W 形）部分，每个部分都有一个较宽的通道区，夹在两个较窄的阻挡区之间。每个部分出现准束缚态的能量取决于结构中相应部分的尺寸参数。我们研究了通过准结合态的传输如何受到触点边缘状态和尺寸参数（如势垒长度）以及环境温度的影响。我们将研究结果与单部分连接触点的热电阻进行了比较。对于触点之间上下部分不对称的热电阻，可以观察到不同能量下的传输峰值。然后利用这一点创建了两个负微分电阻 (NDR) 峰值。在数值计算中，采用了基于近邻紧密结合模型的非平衡格林函数形式主义（NEGF）。
{"title":"Graphene nanoribbon resonant tunneling diode with dual connection between contacts","authors":"","doi":"10.1016/j.physb.2024.416598","DOIUrl":"10.1016/j.physb.2024.416598","url":null,"abstract":"<div><div>In this paper, we numerically study the transport properties of a resonant tunneling diode (RTD) based on graphene nanoribbon (GNR) with an H-type antidote between the contacts. The structure may also be thought of as having two parallel (W-shape) parts connecting the contacts, each having a wider channel region sandwiched between two narrower barrier regions. The energy at which quasi-bound states occur in each part depends on the dimensional parameters of the respective portion in the structure. We study how the transmission through quasi-bound states is influenced by the edge states on the contacts and dimensional parameters such as barrier length and also by the ambient temperature. The results are compared with those of an RTD with a single part connecting the contacts. Transmission peaks at different energies are observed for an RTD with asymmetrical lower and upper parts between the contacts. This is then utilized for the creation of two negative differential resistance (NDR) peaks. For numerical computation, the non-equilibrium Green’s function formalism (NEGF) based on the nearest neighbor tight-binding model is employed.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-10DOI: 10.1016/j.physb.2024.416602
We experimentally study electron transport across a single planar junction between the indium electrode and MnTe altermagnet candidate. We confirm standard Ohmic behavior with strictly linear current–voltage curves above the indium critical field or temperature, although with high, about 100 kOhm, junction resistance. At low temperatures and in zero magnetic field, we observe a well-developed Andreev curve with the pronounced coherence peaks, which cannot be normally expected for these high values of normal junction resistance. The conclusion on the Andreev reflection is also supported by suppression in magnetic field, as well as by universality of the observed behavior for all of the investigated samples. The experimental results can be explained by specifics of Andreev transport through the disordered region at the superconductor-altermagnet interface. Due to a different set of restrictions on the possibility of Andreev reflection, an altermagnet suffers from the presence of disorder less than a normal spin-degenerate metal, so the conductance enhancement is retained throughout the superconducting gap.
{"title":"Andreev reflection for MnTe altermagnet candidate","authors":"","doi":"10.1016/j.physb.2024.416602","DOIUrl":"10.1016/j.physb.2024.416602","url":null,"abstract":"<div><div>We experimentally study electron transport across a single planar junction between the indium electrode and MnTe altermagnet candidate. We confirm standard Ohmic behavior with strictly linear current–voltage curves above the indium critical field or temperature, although with high, about 100 kOhm, junction resistance. At low temperatures and in zero magnetic field, we observe a well-developed Andreev curve with the pronounced coherence peaks, which cannot be normally expected for these high values of normal junction resistance. The conclusion on the Andreev reflection is also supported by suppression in magnetic field, as well as by universality of the observed behavior for all of the investigated samples. The experimental results can be explained by specifics of Andreev transport through the disordered region at the superconductor-altermagnet interface. Due to a different set of restrictions on the possibility of Andreev reflection, an altermagnet suffers from the presence of disorder less than a normal spin-degenerate metal, so the conductance enhancement is retained throughout the superconducting gap.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-10DOI: 10.1016/j.physb.2024.416614
In this work, LaCrO3 (LCO) and LaCr0.5Ni0.5O3 (LCNO) chromite samples are synthesized through sol-gel auto-combustion method. The effect of nickel content in LaCrO3 is studied with respect to their structural, optical and dielectric properties. X-ray diffraction (XRD) confirmed the single-phase orthorhombic crystal structure with space group (Pnma) of both the samples. The obtained lattice parameters and bond lengths via Rietveld refinement analysis are found to be increased with Ni content. The crystallite sizes of LCO and LCNO are calculated using Scherrer's equation, which are found to be 22 nm and 28 nm, respectively. The Fourier-transform infrared (FTIR) spectroscopy of both the samples confirmed the different functional groups and having two main characteristic bands at 420 and 620 cm−1. Scanning electron microscopy (SEM) shows the variation in the surface morphology with Ni doping. Energy-dispersive X-ray (EDX) spectroscopy confirm the elemental compositions of the samples with their nominal atomic and weight percentages. UV–Visible spectroscopy reveals the decrease in the band gap energy from 2.60 eV to 2.30 eV with Ni doping. Raman spectra of LCO and LCNO samples, confirmed the formation of single-phase orthorhombic structure. The Raman active modes are also shifted with Ni doping due to lattice strain and crystal defects. Photoluminescence (PL) absorption intensities are varied, which is due to the creation of defects with Ni doping in LCO crystal structure. The electronic states of constituent element are obtained using X-ray photoelectron spectroscopy (XPS). Dielectric constant (εʹ), loss, and a.c. conductivity (σac) are studied based on the Ni2+/Ni3+ substitution in LCO at Cr site.
{"title":"Influence of Ni doping on microstructural, optical and dielectric properties of lanthanum-based chromite","authors":"","doi":"10.1016/j.physb.2024.416614","DOIUrl":"10.1016/j.physb.2024.416614","url":null,"abstract":"<div><div>In this work, LaCrO<sub>3</sub> (LCO) and LaCr<sub>0.5</sub>Ni<sub>0.5</sub>O<sub>3</sub> (LCNO) chromite samples are synthesized through sol-gel auto-combustion method. The effect of nickel content in LaCrO<sub>3</sub> is studied with respect to their structural, optical and dielectric properties. X-ray diffraction (XRD) confirmed the single-phase orthorhombic crystal structure with space group (<em>Pnma</em>) of both the samples. The obtained lattice parameters and bond lengths via Rietveld refinement analysis are found to be increased with Ni content. The crystallite sizes of LCO and LCNO are calculated using Scherrer's equation, which are found to be 22 nm and 28 nm, respectively. The Fourier-transform infrared (FTIR) spectroscopy of both the samples confirmed the different functional groups and having two main characteristic bands at 420 and 620 cm<sup>−1</sup>. Scanning electron microscopy (SEM) shows the variation in the surface morphology with Ni doping. Energy-dispersive X-ray (EDX) spectroscopy confirm the elemental compositions of the samples with their nominal atomic and weight percentages. UV–Visible spectroscopy reveals the decrease in the band gap energy from 2.60 eV to 2.30 eV with Ni doping. Raman spectra of LCO and LCNO samples, confirmed the formation of single-phase orthorhombic structure. The Raman active modes are also shifted with Ni doping due to lattice strain and crystal defects. Photoluminescence (PL) absorption intensities are varied, which is due to the creation of defects with Ni doping in LCO crystal structure. The electronic states of constituent element are obtained using X-ray photoelectron spectroscopy (XPS). Dielectric constant (εʹ), loss, and a.c. conductivity (σ<sub>ac</sub>) are studied based on the Ni<sup>2+</sup>/Ni<sup>3+</sup> substitution in LCO at Cr site.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.physb.2024.416609
In this study, the structural, electrical, and thermoelectric properties for three phases of two-dimensional have been investigated using first-principles study and semiclassic Boltzmann theory. The results of the electronic density of states have represented band gaps of 1.026, 1.021, and 1.048 eV for phase 1, phase 2, and phase 3, respectively. Furthermore, the largest value of the Seebeck coefficient at 300 K belonged to phase 2 with a value of 1585.21 V/K at the chemical potential of 0.45 eV. In addition, the largest value of electrical conductivity per relaxation time was related to phase 1 at 300 K with the value of 3.42 × 1020 m−1 s−1 at the chemical potential of -1.94 eV. Moreover, the largest value of the thermoelectric power factor per relaxation time occurred for phase 1 at 700 K with a value of 48.62 × 1016 W m−1 K−2 s−1 at the chemical potential of -1.17 eV.
本研究采用第一性原理研究和半经典玻尔兹曼理论，对二维 WTe2 三相的结构、电学和热电性能进行了研究。电子态密度的结果表明，相 1、相 2 和相 3 的带隙分别为 1.026、1.021 和 1.048 eV。此外，在化学势为 0.45 eV 时，相 2 在 300 K 的塞贝克系数值最大，为 1585.21 μV/K。此外，在 300 K 时，化学势为 -1.94 eV 时，每个弛豫时间的最大电导率值与相 1 有关，其值为 3.42 × 1020 Ω-1 m-1 s-1。此外，在化学势为 -1.17 eV 时，相 1 在 700 K 时的单位弛豫时间热电功率因数值最大，为 48.62 × 1016 μW m-1 K-2 s-1。
{"title":"Exploration of structural, electrical, and thermoelectric properties of two-dimensional WTe2 in three phases through ab initio investigations","authors":"","doi":"10.1016/j.physb.2024.416609","DOIUrl":"10.1016/j.physb.2024.416609","url":null,"abstract":"<div><div>In this study, the structural, electrical, and thermoelectric properties for three phases of two-dimensional <span><math><msub><mrow><mi>WTe</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> have been investigated using first-principles study and semiclassic Boltzmann theory. The results of the electronic density of states have represented band gaps of 1.026, 1.021, and 1.048 eV for phase 1, phase 2, and phase 3, respectively. Furthermore, the largest value of the Seebeck coefficient at 300 K belonged to phase 2 with a value of 1585.21 <span><math><mi>μ</mi></math></span>V/K at the chemical potential of 0.45 eV. In addition, the largest value of electrical conductivity per relaxation time was related to phase 1 at 300 K with the value of 3.42 × 10<sup>20</sup> <span><math><msup><mrow><mi>Ω</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> m<sup>−1</sup> s<sup>−1</sup> at the chemical potential of -1.94 eV. Moreover, the largest value of the thermoelectric power factor per relaxation time occurred for phase 1 at 700 K with a value of 48.62 × 10<sup>16</sup> <span><math><mi>μ</mi></math></span>W m<sup>−1</sup> K<sup>−2</sup> s<sup>−1</sup> at the chemical potential of -1.17 eV.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.physb.2024.416611
All-d-metal Heusler-type Ni-Mn-Ti alloys have emerged as a research focus in the field of elastocaloric refrigeration due to their remarkable elastocaloric effect. However, the mechanical properties of these materials present a challenge for their engineering applications. In this work, Ni37Co13Mn33.5Ti16.5 alloys with varying particle sizes were successfully prepared under different conditions using spark plasma sintering. The influence of particle size on the microstructure, mechanical properties and the elastocaloric effect were systematically explored. The results indicate that smaller particle sizes can significantly enhance mechanical properties during the SPS process, primarily due to grain refinement and the presence of Ti-rich second phases within the grains. Notably, compressive strength and fracture strain reached as high as 2225 MPa and 33 %, respectively, marking an increase of 145.9 % and 312.5 % over the as-cast alloy. Additionally, an unprecedently adiabatic temperature variation of 31.2 K was obtained upon loading in the sintered Ni-(Co)-Mn-Ti shape memory alloys.
{"title":"Excellent mechanical properties and giant room-temperature elastocaloric effect in spark plasma sintered Ni-Co-Mn-Ti shape memory alloy","authors":"","doi":"10.1016/j.physb.2024.416611","DOIUrl":"10.1016/j.physb.2024.416611","url":null,"abstract":"<div><div>All-d-metal Heusler-type Ni-Mn-Ti alloys have emerged as a research focus in the field of elastocaloric refrigeration due to their remarkable elastocaloric effect. However, the mechanical properties of these materials present a challenge for their engineering applications. In this work, Ni<sub>37</sub>Co<sub>13</sub>Mn<sub>33.5</sub>Ti<sub>16.5</sub> alloys with varying particle sizes were successfully prepared under different conditions using spark plasma sintering. The influence of particle size on the microstructure, mechanical properties and the elastocaloric effect were systematically explored. The results indicate that smaller particle sizes can significantly enhance mechanical properties during the SPS process, primarily due to grain refinement and the presence of Ti-rich second phases within the grains. Notably, compressive strength and fracture strain reached as high as 2225 MPa and 33 %, respectively, marking an increase of 145.9 % and 312.5 % over the as-cast alloy. Additionally, an unprecedently adiabatic temperature variation of 31.2 K was obtained upon loading in the sintered Ni-(Co)-Mn-Ti shape memory alloys.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.physb.2024.416612
In this paper, we report the investigation of the structure evolution and dielectric properties of α-GeO2 under compression using in-situ Raman spectroscopic measurements, alternate current impedance spectroscopic measurements, and first-principal calculations. It is discovered that the coordination number of Ge in α-GeO2 increases from 4 to 6 at 5.0 GPa, while an amorphous state forms at 11.5 GPa and maintains to ambient conditions. The alternate current impedance spectroscopy measurements revealed that the variation of electrical resistance shows opposite tendencies at pressures against that of the coordination number. This phenomenon is ascribed to the pressure-induced emergence of unbonded oxygen atoms, and thus the increase of the concentration of oxygen ions in the GeO4 tetrahedra. Meanwhile，it is found that the application of pressure-induced amorphization improves the dielectric properties to a certain extent, which is of significant importance to provide a valuable approach for the synthesis of amorphous oxides with better dielectric properties.
{"title":"Pressure-induced amorphization in α-GeO2: Structural evolution and improved dielectric properties","authors":"","doi":"10.1016/j.physb.2024.416612","DOIUrl":"10.1016/j.physb.2024.416612","url":null,"abstract":"<div><div>In this paper, we report the investigation of the structure evolution and dielectric properties of α-GeO<sub>2</sub> under compression using <em>in-situ</em> Raman spectroscopic measurements, alternate current impedance spectroscopic measurements, and first-principal calculations. It is discovered that the coordination number of Ge in α-GeO<sub>2</sub> increases from 4 to 6 at 5.0 GPa, while an amorphous state forms at 11.5 GPa and maintains to ambient conditions. The alternate current impedance spectroscopy measurements revealed that the variation of electrical resistance shows opposite tendencies at pressures against that of the coordination number. This phenomenon is ascribed to the pressure-induced emergence of unbonded oxygen atoms, and thus the increase of the concentration of oxygen ions in the GeO<sub>4</sub> tetrahedra. Meanwhile，it is found that the application of pressure-induced amorphization improves the dielectric properties to a certain extent, which is of significant importance to provide a valuable approach for the synthesis of amorphous oxides with better dielectric properties.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.physb.2024.416608
This study examines the physicochemical and electrochemical characteristics of hydrothermally produced, 800°C-annealed pure and Fe3+ doped (0.02, 0.04, and 0.06 M) NiO nanoparticles(NPs).The face-centred cubic structure of NiO NPs was verified by XRD analysis, and doping resulted in a decrease in crystallite size from 43.92 nm to 19.67 nm.FE-SEM revealed dense and irregularly arranged granular morphologies, while EDAX confirmed successful Fe3+ incorporation into NiO matrix. UV–Vis DRS showed an increase in bandgap energy from 3.15 eV to 3.71 eV. XPS confirmed the presence of Ni2+ and Fe3+ with their elemental compositions. According to BET analysis, Fe3+ doping increases pore size and specific surface area, which raises specific capacitance.VSM analysis of pure and Fe3+ doped NiO NPs demonstrated a transition from a weak ferromagnetic to a distinctive ferromagnetic behaviour, which is beneficial for energy storage as well as data storage applications.The electrochemical studies showed that 0.06 M Fe3+ doped NiO had the maximum specific capacitance of 360.96 F g−1 at the scan rate of 10 mV s−1and EIS Nyquist plots showed enhanced electrical conductivity. These results highlight the possibility of Fe3+ doped NiO NPs as excellent electrode materials for high-efficiency supercapacitors.
{"title":"Enhancement of supercapacitor efficiency by Fe3+ doping in hydrothermally synthesized NiO nanoparticles","authors":"","doi":"10.1016/j.physb.2024.416608","DOIUrl":"10.1016/j.physb.2024.416608","url":null,"abstract":"<div><div>This study examines the physicochemical and electrochemical characteristics of hydrothermally produced, 800°C-annealed pure and Fe<sup>3+</sup> doped (0.02, 0.04, and 0.06 M) NiO nanoparticles(NPs).The face-centred cubic structure of NiO NPs was verified by XRD analysis, and doping resulted in a decrease in crystallite size from 43.92 nm to 19.67 nm.FE-SEM revealed dense and irregularly arranged granular morphologies, while EDAX confirmed successful Fe<sup>3+</sup> incorporation into NiO matrix. UV–Vis DRS showed an increase in bandgap energy from 3.15 eV to 3.71 eV. XPS confirmed the presence of Ni<sup>2+</sup> and Fe<sup>3+</sup> with their elemental compositions. According to BET analysis, Fe<sup>3+</sup> doping increases pore size and specific surface area, which raises specific capacitance.VSM analysis of pure and Fe<sup>3+</sup> doped NiO NPs demonstrated a transition from a weak ferromagnetic to a distinctive ferromagnetic behaviour, which is beneficial for energy storage as well as data storage applications.The electrochemical studies showed that 0.06 M Fe<sup>3+</sup> doped NiO had the maximum specific capacitance of 360.96 F g<sup>−1</sup> at the scan rate of 10 mV s<sup>−1</sup>and EIS Nyquist plots showed enhanced electrical conductivity. These results highlight the possibility of Fe<sup>3+</sup> doped NiO NPs as excellent electrode materials for high-efficiency supercapacitors.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-09DOI: 10.1016/j.physb.2024.416578
{"title":"Corrigendum to ‘Slip to twinning to slip transition in polycrystalline BCC-Fe: Effect of grain size’ [Physica B 694 / PHYSB-D-24-01567R1]","authors":"","doi":"10.1016/j.physb.2024.416578","DOIUrl":"10.1016/j.physb.2024.416578","url":null,"abstract":"","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-08DOI: 10.1016/j.physb.2024.416607
Zn0.9Mn0.05Fe0.05O were synthesized by rf-magnetron sputtering in an argon gas environment show a hexagonal wurtzite structure without any secondary phases of dopants MnO or Fe2O3. The crystallite (D) parameters estimated from the XRD pattern disclose a significant decrease with argon partial gas pressure from 3.34 to 11.80 nm. The surface morphology of as-deposited films has a dense columnar microstructure with an average grain size of about 14–18 nm with roughness (RMS) from ∼2.86 to 7.67 nm. The sputtered thin films exhibit high optical transmittance in the visible range with a significant redshift as a function of working pressure. The energy band gap shows a slight increase with gas pressure in the range of about ∼3.05–3.36 eV. The films deposited for argon gas pressures of 12 & 15 mTorr have room-temperature ferromagnetism due to oxygen vacancies/defect concentrations in the host ZnO matrix.
{"title":"Optical and magnetic properties of Zn0.9Mn0.05Fe0.05O thin films deposited by RF-magnetron sputtering","authors":"","doi":"10.1016/j.physb.2024.416607","DOIUrl":"10.1016/j.physb.2024.416607","url":null,"abstract":"<div><div>Zn<sub>0.9</sub>Mn<sub>0.05</sub>Fe<sub>0.05</sub>O were synthesized by rf-magnetron sputtering in an argon gas environment show a hexagonal wurtzite structure without any secondary phases of dopants MnO or Fe<sub>2</sub>O<sub>3</sub>. The crystallite (D) parameters estimated from the XRD pattern disclose a significant decrease with argon partial gas pressure from 3.34 to 11.80 nm. The surface morphology of as-deposited films has a dense columnar microstructure with an average grain size of about 14–18 nm with roughness (RMS) from ∼2.86 to 7.67 nm. The sputtered thin films exhibit high optical transmittance in the visible range with a significant redshift as a function of working pressure. The energy band gap shows a slight increase with gas pressure in the range of about ∼3.05–3.36 eV. The films deposited for argon gas pressures of 12 & 15 mTorr have room-temperature ferromagnetism due to oxygen vacancies/defect concentrations in the host ZnO matrix.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-08DOI: 10.1016/j.physb.2024.416600
BaFe12O19 (barium ferrite, i.e., BaF) nanoparticles, Co0.5Zn0.5Fe2O4 (cobalt zinc ferrite, i.e, CZF) nanoparticles and their nanocomposite were synthesized for the investigation of electrical, magnetic, dielectric, and electrochemical properties. The X-ray diffraction (XRD) pattern revealed the formation of hexagonal structure for BaF nanoparticles and cubic structure for CZF nanoparticles with crystallite size of 32.44 nm and 31.30 nm, respectively. Whereas, for nanocomposite, the crystallite size obtained is 34.21 nm were shifting of peaks revealed the formation of nanocomposite. The Fourier transform Infrared (FTIR) spectra revealed the presence of metal-oxygen vibrational peaks for all the samples. The dielectric data revealed the increase in dielectric constant of nanocomposite as compared to pristine CZF whereas, loss reduced for nanocomposite significantly. Single semicircle in Nyquist plot for all the samples revealed the contribution of grain resistance in impedance. The hysteresis loop showed the increase in specific saturation magnetization from 16.963 emu/g to 21.305 emu/g for nanocomposite when compared with pristine BaF. Whereas specific remnant magnetization increased to 10.305 emu/g for nanocomposites. The electrochemical properties presented by Cyclic voltammetry showed the presence of cathodic and anodic peaks which revealed the presence of redox reaction in all samples. The specific capacitance calculated for all samples at different scan rate revealed that a nanocomposite showed highest Cs value 16.43 F/g at 25 mV, whereas it increased to 27.01 F/g, 35.93 F/g and 38.87 F/g with the increase in scan rate to 50 mV, 75 mV and 100 mV, respectively.
{"title":"Investigation of electrical, dielectric, magnetic and electrochemical characteristics of a BaFe12O19/Co0.5Zn0.5Fe2O4 nanocomposite","authors":"","doi":"10.1016/j.physb.2024.416600","DOIUrl":"10.1016/j.physb.2024.416600","url":null,"abstract":"<div><div>BaFe<sub>12</sub>O<sub>19</sub> (barium ferrite, i.e., BaF) nanoparticles, Co<sub>0.5</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4</sub> (cobalt zinc ferrite, i.e, CZF) nanoparticles and their nanocomposite were synthesized for the investigation of electrical, magnetic, dielectric, and electrochemical properties. The X-ray diffraction (XRD) pattern revealed the formation of hexagonal structure for BaF nanoparticles and cubic structure for CZF nanoparticles with crystallite size of 32.44 nm and 31.30 nm, respectively. Whereas, for nanocomposite, the crystallite size obtained is 34.21 nm were shifting of peaks revealed the formation of nanocomposite. The Fourier transform Infrared (FTIR) spectra revealed the presence of metal-oxygen vibrational peaks for all the samples. The dielectric data revealed the increase in dielectric constant of nanocomposite as compared to pristine CZF whereas, loss reduced for nanocomposite significantly. Single semicircle in Nyquist plot for all the samples revealed the contribution of grain resistance in impedance. The hysteresis loop showed the increase in specific saturation magnetization from 16.963 emu/g to 21.305 emu/g for nanocomposite when compared with pristine BaF. Whereas specific remnant magnetization increased to 10.305 emu/g for nanocomposites. The electrochemical properties presented by Cyclic voltammetry showed the presence of cathodic and anodic peaks which revealed the presence of redox reaction in all samples. The specific capacitance calculated for all samples at different scan rate revealed that a nanocomposite showed highest Cs value 16.43 F/g at 25 mV, whereas it increased to 27.01 F/g, 35.93 F/g and 38.87 F/g with the increase in scan rate to 50 mV, 75 mV and 100 mV, respectively.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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