Pub Date : 2023-11-02DOI: 10.1088/1361-6463/ad066c
Yujia Zhang, Yu He, Xuhan Guo, Yikai Su
A novel non-volatile optical filter with a large bandwidth (BW) and extinction ratio (ER) tunability is first experimentally demonstrated by introducing an all-optical phase change of Ge2Sb2Te5 (GST). The Si-GST hybrid device promises flexible multi-level regulation of essential filter parameters in an ultra-compact footprint of 30 μm × 13 μm. Ultra-low power consumption is realised on account of the saving of external static power that is required in other electric-optic or optic-optic-driven filters. The GST is loaded onto two triple-waveguide directional couplers located at the coupling regions of an add-drop microring resonator. By initiating the GST phase transition with pump optical pulses, the transmitted optical power to the cross port of the triple-waveguide coupler is adjustable, hence influencing the coupling efficiency states of the microring filter. Consequently, a tunable on-off ER from 0.7 dB to 18.2 dB and a tunable BW from 0.6 nm to 3.3 nm are experimentally obtained with the aid of optically manipulating the crystallization degree of GST. Our device potentially enables the realisation of high-density photonic integrated circuits, especially in dense wavelength division multiplexing networks.
{"title":"Non-volatile optical filter based on a Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> assisted microring with a tunable bandwidth and extinction ratio","authors":"Yujia Zhang, Yu He, Xuhan Guo, Yikai Su","doi":"10.1088/1361-6463/ad066c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad066c","url":null,"abstract":"A novel non-volatile optical filter with a large bandwidth (BW) and extinction ratio (ER) tunability is first experimentally demonstrated by introducing an all-optical phase change of Ge2Sb2Te5 (GST). The Si-GST hybrid device promises flexible multi-level regulation of essential filter parameters in an ultra-compact footprint of 30 μm × 13 μm. Ultra-low power consumption is realised on account of the saving of external static power that is required in other electric-optic or optic-optic-driven filters. The GST is loaded onto two triple-waveguide directional couplers located at the coupling regions of an add-drop microring resonator. By initiating the GST phase transition with pump optical pulses, the transmitted optical power to the cross port of the triple-waveguide coupler is adjustable, hence influencing the coupling efficiency states of the microring filter. Consequently, a tunable on-off ER from 0.7 dB to 18.2 dB and a tunable BW from 0.6 nm to 3.3 nm are experimentally obtained with the aid of optically manipulating the crystallization degree of GST. Our device potentially enables the realisation of high-density photonic integrated circuits, especially in dense wavelength division multiplexing networks.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"40 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-02DOI: 10.1088/1361-6463/ad0569
Jessica Carolina Delgado Alvarez, Chiara Provenzano, Marcella Marra, Maurizio Martino, Anna Grazia Monteduro, Sandra Moretto, Felix Pino, Matteo Polo, Gianluca Quarta, Anna Paola Caricato
Abstract Metal halide perovskite materials have received significant attention in recent years due to their promising properties and potential applications, particularly their use as scintillator detectors, which is rapidly emerging due to their promising advantages as detectors, such as low costs, fast response, high quantum yield, strong absorption, scalability, flexibility, and emission wavelength tunability. Given the effectiveness of perovskites as α particle detectors and the potential of 10 B as a neutron converter, in this paper a 10 B converting layer was coupled with an all-inorganic lead halide perovskite (CsPbBr 3 ) layer aiming to create a thermal neutron detector. Specifically, a 1 µ m thin film of 10 B and a 1 µ m thin layer of CsPbBr 3 were deposited on a suitable substrate using a laser ablation process. The fabricated detector was subjected to a comprehensive characterization, including structural, morphological, and detection properties. As output, the films exhibit macroscopically uniform behavior and good adhesion to the substrate. In terms of thermal neutron efficiency, an efficiency of (7.9 ± 0.3)% was determined with respect to a commercial detector (EJ-426), which corresponds to an intrinsic efficiency of (2.5 ± 0.1)%. Also, Monte Carlo simulations were conducted, and the optimum value of the 10 B layer thickness was found to be 2.5 µ m.
{"title":"Study of a metal-halide perovskite CsPbBr<sub>3</sub> thin film deposited on a <sup>10</sup>B layer for neutron detection","authors":"Jessica Carolina Delgado Alvarez, Chiara Provenzano, Marcella Marra, Maurizio Martino, Anna Grazia Monteduro, Sandra Moretto, Felix Pino, Matteo Polo, Gianluca Quarta, Anna Paola Caricato","doi":"10.1088/1361-6463/ad0569","DOIUrl":"https://doi.org/10.1088/1361-6463/ad0569","url":null,"abstract":"Abstract Metal halide perovskite materials have received significant attention in recent years due to their promising properties and potential applications, particularly their use as scintillator detectors, which is rapidly emerging due to their promising advantages as detectors, such as low costs, fast response, high quantum yield, strong absorption, scalability, flexibility, and emission wavelength tunability. Given the effectiveness of perovskites as α particle detectors and the potential of 10 B as a neutron converter, in this paper a 10 B converting layer was coupled with an all-inorganic lead halide perovskite (CsPbBr 3 ) layer aiming to create a thermal neutron detector. Specifically, a 1 µ m thin film of 10 B and a 1 µ m thin layer of CsPbBr 3 were deposited on a suitable substrate using a laser ablation process. The fabricated detector was subjected to a comprehensive characterization, including structural, morphological, and detection properties. As output, the films exhibit macroscopically uniform behavior and good adhesion to the substrate. In terms of thermal neutron efficiency, an efficiency of (7.9 ± 0.3)% was determined with respect to a commercial detector (EJ-426), which corresponds to an intrinsic efficiency of (2.5 ± 0.1)%. Also, Monte Carlo simulations were conducted, and the optimum value of the 10 B layer thickness was found to be 2.5 µ m.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"50 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract An unexpectedly larger current-induced spin–orbit torque in oxidized Cu (CuO x )/ferromagnet (FM) than heavy-metal/FM has recently attracted intense attention in spintronic studies. Although the two mechanisms, interfacial Rashba Edelstein effect and spin-vorticity coupling, have been put forward based on the two different conductive features of CuO x , i.e. electrical insulator and gradient of electrical mobility, the detailed investigation of transport of CuO x is still lacking. Here we experimentally report the positive and negative anomalous Hall effect (AHE) in naturally oxidized normal-metal Al/Cu double films. We found that the onset temperature of AHE corresponds to magnetic transition temperature of CuO x . Furthermore, by comparing Hall resistance of the crystalline and amorphous Cu/Al double films, we identify that the positive anomalous Hall resistance attributes to magnetic moment of CuO x itself, while the negative anomalous Hall resistance can originate from the spin or orbital currents generated at the CuO x /AlO x interface interact with magnetization of CuO x and its inverse process.
{"title":"Anomalous Hall effect in naturally oxidized normal-metal Al/Cu double films","authors":"Lijuan Zhao, Yuzhi Li, Yongzuo Wang, Peng Chen, Bing Lv, Cunxu Gao","doi":"10.1088/1361-6463/ad06ed","DOIUrl":"https://doi.org/10.1088/1361-6463/ad06ed","url":null,"abstract":"Abstract An unexpectedly larger current-induced spin–orbit torque in oxidized Cu (CuO x )/ferromagnet (FM) than heavy-metal/FM has recently attracted intense attention in spintronic studies. Although the two mechanisms, interfacial Rashba Edelstein effect and spin-vorticity coupling, have been put forward based on the two different conductive features of CuO x , i.e. electrical insulator and gradient of electrical mobility, the detailed investigation of transport of CuO x is still lacking. Here we experimentally report the positive and negative anomalous Hall effect (AHE) in naturally oxidized normal-metal Al/Cu double films. We found that the onset temperature of AHE corresponds to magnetic transition temperature of CuO x . Furthermore, by comparing Hall resistance of the crystalline and amorphous Cu/Al double films, we identify that the positive anomalous Hall resistance attributes to magnetic moment of CuO x itself, while the negative anomalous Hall resistance can originate from the spin or orbital currents generated at the CuO x /AlO x interface interact with magnetization of CuO x and its inverse process.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"38 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-02DOI: 10.1088/1361-6463/ad0912
Xiongying Chao, Yan Xu, Feng Huang, Zhaoyang Chen
Abstract We design a graphene-based broadband tunable terahertz metamaterial absorber (MMA). Its structure consists of a surface graphene pattern layer, a medium layer and an underlying metal film. CST simulation results show that the absorption bandwidth for more than 90% absorption rate reaches 2.12 THz, and the range is 3.2-5.32 THz. The absorption bandwidth for more than 99% absorption rate reaches 1.38 THz, and the range is 3.45-4.83 THz, which was not achieved by most of the previous MMA. Multiple reflection interference theory is used to confirm the simulation results. In order to explore the physical mechanism of wideband absorption, we study the surface electric field distribution of the structure. We also find that the absorber has polarization insensitivity and wide-angle incidence characteristics. The absorption frequency of the absorber can be adjusted by changing the chemical potential of graphene. Therefore, the absorber has potential applications in terahertz absorption, filtering and sensing.
{"title":"A High-quality Broadband Tunable Terahertz Metamaterial Absorber Based on Graphene","authors":"Xiongying Chao, Yan Xu, Feng Huang, Zhaoyang Chen","doi":"10.1088/1361-6463/ad0912","DOIUrl":"https://doi.org/10.1088/1361-6463/ad0912","url":null,"abstract":"Abstract We design a graphene-based broadband tunable terahertz metamaterial absorber (MMA). Its structure consists of a surface graphene pattern layer, a medium layer and an underlying metal film. CST simulation results show that the absorption bandwidth for more than 90% absorption rate reaches 2.12 THz, and the range is 3.2-5.32 THz. The absorption bandwidth for more than 99% absorption rate reaches 1.38 THz, and the range is 3.45-4.83 THz, which was not achieved by most of the previous MMA. Multiple reflection interference theory is used to confirm the simulation results. In order to explore the physical mechanism of wideband absorption, we study the surface electric field distribution of the structure. We also find that the absorber has polarization insensitivity and wide-angle incidence characteristics. The absorption frequency of the absorber can be adjusted by changing the chemical potential of graphene. Therefore, the absorber has potential applications in terahertz absorption, filtering and sensing.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"13 S3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135875576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.1088/1361-6463/ad030c
Wasim Akram, Muireann de h-Óra, Manisha Bansal, Rajatava Mukhopadhyay, Judith L MacManus-Driscoll, Tuhin Maity
Abstract The table-like behavior of the magnetic entropy change is generally observed in rare-earth-based alloys (e.g. La(Fe,Si) 13 , Gd 50 Co 45 Fe 5 , Gd 56 Ni 15 Al 27 Zr 2 , Gd (1−x−y) Co x Al y etc). Here, we report similar table-like behavior in a bulk perovskite Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite system with a working temperature span of ∼80 K for a field change of ∼70 kOe. AC susceptibility and time-dependent DC magnetization relaxation measurements confirm the presence of interacting ferromagnetic clusters with a Vogel–Fulcher freezing temperature of T0∼ 42.7 K. The Langevin function fittings of the isothermal magnetization curves show a non-monotonous variation of cluster size with temperature. We propose a model for the high-field dependency of the ferromagnetic cluster coupling in the composite system. This widens the transition temperature region of long-range order formation and hence gives rise to the table-like magnetocaloric effect in Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite systems.
摘要稀土基合金(如La(Fe,Si) 13、Gd 50 Co 45 Fe 5、Gd 56 Ni 15 Al 27 Zr 2、Gd(1−x−y) Co x Al y等)的磁熵变化普遍呈表状。在这里，我们报告了块状钙钛矿Eu 0.5 Sr 0.5 mno3 - euumno3复合体系中类似的表状行为，其工作温度范围为~ 80 K，场变化为~ 70 kOe。交流磁化率和随时间变化的直流磁化弛豫测量证实，在Vogel-Fulcher冻结温度为T 0 ~ 42.7 K时，存在相互作用的铁磁团簇。等温磁化曲线的朗热万函数拟合显示出团簇大小随温度的非单调变化。我们提出了复合系统中铁磁团簇耦合的高场依赖性模型。这扩大了Eu 0.5 Sr 0.5 mno3 - euumno3复合体系的长程有序形成的转变温度区域，从而产生了表状磁热效应。
{"title":"Table-like magnetocaloric effect due to field induced inter-cluster interactions in Eu<sub>0.5</sub>Sr<sub>0.5</sub>MnO<sub>3</sub>-EuMnO<sub>3</sub> composites","authors":"Wasim Akram, Muireann de h-Óra, Manisha Bansal, Rajatava Mukhopadhyay, Judith L MacManus-Driscoll, Tuhin Maity","doi":"10.1088/1361-6463/ad030c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad030c","url":null,"abstract":"Abstract The table-like behavior of the magnetic entropy change is generally observed in rare-earth-based alloys (e.g. La(Fe,Si) 13 , Gd 50 Co 45 Fe 5 , Gd 56 Ni 15 Al 27 Zr 2 , Gd <?CDATA $_{(1-x-y)}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msub> <mml:mi /> <mml:mrow> <mml:mo stretchy=\"false\">(</mml:mo> <mml:mn>1</mml:mn> <mml:mo>−</mml:mo> <mml:mi>x</mml:mi> <mml:mo>−</mml:mo> <mml:mi>y</mml:mi> <mml:mo stretchy=\"false\">)</mml:mo> </mml:mrow> </mml:msub> </mml:math> Co x Al y etc). Here, we report similar table-like behavior in a bulk perovskite Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite system with a working temperature span of ∼80 K for a field change of ∼70 kOe. AC susceptibility and time-dependent DC magnetization relaxation measurements confirm the presence of interacting ferromagnetic clusters with a Vogel–Fulcher freezing temperature of <?CDATA $T_0 sim$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msub> <mml:mi>T</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>∼</mml:mo> </mml:math> 42.7 K. The Langevin function fittings of the isothermal magnetization curves show a non-monotonous variation of cluster size with temperature. We propose a model for the high-field dependency of the ferromagnetic cluster coupling in the composite system. This widens the transition temperature region of long-range order formation and hence gives rise to the table-like magnetocaloric effect in Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite systems.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"20 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135061698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.1088/1361-6463/ad039a
Muralidhar Miryala, Malik Shadab, Srikanth Sai Arvapalli, Milos Jirsa, Jacques G Noudem
Abstract Although the fascinating effect of superconductivity was discovered more than 100 years ago, only a few low-temperature superconductors, especially Nb 3 Sn and NbTi, have reached everyday-life use. After the discovery of superconductivity in MgB 2 in 2001, a boom appeared in interest in employing MgB 2 in commercial applications, facilitated by simple crystallographic structure, high critical temperature, low-cost raw ingredients, simple and fast production, and other advantages for moderate temperature applications. It only lacks high flux pinning and good mechanical performance. In this review, the implications of manufacturing procedures on the superconducting properties, crystal and electronic structure of MgB 2 are discussed. The advantages and drawbacks of various manufacturing processes will be presented, as well as the ways how to improve MgB 2 superconducting performance. The impact of oxygen reduction, elements doping, the introduction of defects and additives, and the effect of precursor refinement on superconducting properties are here compiled to give an overview of the progress of flux pinning enhancement in bulk MgB 2 .
{"title":"Review on High-Performance Bulk MgB2 Superconductors","authors":"Muralidhar Miryala, Malik Shadab, Srikanth Sai Arvapalli, Milos Jirsa, Jacques G Noudem","doi":"10.1088/1361-6463/ad039a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad039a","url":null,"abstract":"Abstract Although the fascinating effect of superconductivity was discovered more than 100 years ago, only a few low-temperature superconductors, especially Nb 3 Sn and NbTi, have reached everyday-life use. After the discovery of superconductivity in MgB 2 in 2001, a boom appeared in interest in employing MgB 2 in commercial applications, facilitated by simple crystallographic structure, high critical temperature, low-cost raw ingredients, simple and fast production, and other advantages for moderate temperature applications. It only lacks high flux pinning and good mechanical performance. In this review, the implications of manufacturing procedures on the superconducting properties, crystal and electronic structure of MgB 2 are discussed. The advantages and drawbacks of various manufacturing processes will be presented, as well as the ways how to improve MgB 2 superconducting performance. The impact of oxygen reduction, elements doping, the introduction of defects and additives, and the effect of precursor refinement on superconducting properties are here compiled to give an overview of the progress of flux pinning enhancement in bulk MgB 2 .","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"143 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136102578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Conventional methods using high-purity quartz lenses to control deep-ultraviolet light-emitting diode (DUV-LED) far-field patterns have limitations, including small effective apertures and high cost. We apply phase-type Fresnel zone plates to control the beam angle and enhance light extraction efficiency (LEE) for DUV-LEDs on sapphire and AlN substrates. We demonstrate highly-collimated optics-free DUV-LED emissions with full width at half maximum far-field divergence angles of 40° and 10° on sapphire and AlN substrates at a peak emission wavelength of 279 nm and 273 nm, respectively. LEE enhancements of 1.4 and 1.5 times for DUV-LEDs on sapphire and AlN substrates, respectively, are also achieved.
{"title":"Far-field pattern control and light-extraction enhancement of deep-ultraviolet light-emitting diodes with large-area Fresnel zone plate nano-structures","authors":"Lingjie Wei, Manabu Taniguchi, Guo-Dong Hao, Shin-ichiro Inoue","doi":"10.1088/1361-6463/ad056a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad056a","url":null,"abstract":"Abstract Conventional methods using high-purity quartz lenses to control deep-ultraviolet light-emitting diode (DUV-LED) far-field patterns have limitations, including small effective apertures and high cost. We apply phase-type Fresnel zone plates to control the beam angle and enhance light extraction efficiency (LEE) for DUV-LEDs on sapphire and AlN substrates. We demonstrate highly-collimated optics-free DUV-LED emissions with full width at half maximum far-field divergence angles of 40° and 10° on sapphire and AlN substrates at a peak emission wavelength of 279 nm and 273 nm, respectively. LEE enhancements of 1.4 and 1.5 times for DUV-LEDs on sapphire and AlN substrates, respectively, are also achieved.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135869591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Field-induced metamagnetic behavior and orbital-ordering (OO) in Yb-substituted (PrSr)MnO 3 perovskites have been reported. The occurrence of distortions in the tetragonal crystal lattice leads to a reduction in the Mn−O2−Mn bond angle, which in turn governs the temperature and field-dependent long-range magnetic orderings. Extensive magnetization measurements reveal the high Curie temperature TC ∼ 302 K ferromagnetic (FM) phase and suggest the possibility of the existence of the OO in Pr 0.45– x Yb x Sr 0.55 MnO 3 accompanied by antiferromagnetic (AFM) Néel temperature, TN , as low as 158 K. Irreversible metamagnetic transitions from the AFM phase to the FM phase occur for a specific composition x = 0.05 (Yb5) until T ⩽ 220 K. The admixture of AFM and FM metastable states is quite robust in the investigated system, whereas the AFM state is mediated by Yb 3+ ions, while the FM state arises as a result of field-driven thermo-magnetic kinetics. These results provide a constructive approach for designing novel spin-valve devices.
本文报道了yb取代mno3钙钛矿的场致变磁性和轨道有序。四方晶格中畸变的发生导致Mn−o2−Mn键角的减小，这反过来又控制了温度和场相关的远程磁有序。广泛的磁化测量揭示了高居里温度T C ~ 302 K铁磁(FM)相，并表明在Pr 0.45 - x Yb x Sr 0.55 mno3中存在OO的可能性，并伴有低至158 K的反铁磁(AFM) n温度T N。对于特定成分x = 0.05 (Yb5)，在T≤220 K之前，从AFM相到FM相发生不可逆的变磁转变。在所研究的体系中，AFM和FM亚稳态的混合非常稳定，而AFM状态是由yb3 +离子介导的，而FM状态是由场驱动的热磁动力学引起的。这些结果为设计新型自旋阀装置提供了建设性的思路。
{"title":"Irreversible Metamagnetic Transitions in Yb3+- distorted tetragonal Pr<sub>0.45</sub>Sr<sub>0.55</sub>MnO<sub>3</sub>","authors":"Ravi Kiran Dokala, Shaona Das, Ganesh Jangam, Pankaj Kumar Mishra, Subhash Thota","doi":"10.1088/1361-6463/ad030d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad030d","url":null,"abstract":"Abstract Field-induced metamagnetic behavior and orbital-ordering (OO) in Yb-substituted (PrSr)MnO 3 perovskites have been reported. The occurrence of distortions in the tetragonal crystal lattice leads to a reduction in the <?CDATA ${text{Mn}} - {{text{O}}_{left( 2 right)}} - {text{Mn}}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:mtext>Mn</mml:mtext> </mml:mrow> <mml:mo>−</mml:mo> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext>O</mml:mtext> </mml:mrow> <mml:mrow> <mml:mfenced close=\")\" open=\"(\"> <mml:mn>2</mml:mn> </mml:mfenced> </mml:mrow> </mml:msub> </mml:mrow> <mml:mo>−</mml:mo> <mml:mrow> <mml:mtext>Mn</mml:mtext> </mml:mrow> </mml:math> bond angle, which in turn governs the temperature and field-dependent long-range magnetic orderings. Extensive magnetization measurements reveal the high Curie temperature <?CDATA ${T_{text{C}}}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mtext>C</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> ∼ 302 K ferromagnetic (FM) phase and suggest the possibility of the existence of the OO in Pr 0.45– x Yb x Sr 0.55 MnO 3 accompanied by antiferromagnetic (AFM) Néel temperature, <?CDATA ${T_{text{N}}}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mtext>N</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , as low as 158 K. Irreversible metamagnetic transitions from the AFM phase to the FM phase occur for a specific composition x = 0.05 (Yb5) until <?CDATA $T$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mi>T</mml:mi> </mml:math> ⩽ 220 K. The admixture of AFM and FM metastable states is quite robust in the investigated system, whereas the AFM state is mediated by Yb 3+ ions, while the FM state arises as a result of field-driven thermo-magnetic kinetics. These results provide a constructive approach for designing novel spin-valve devices.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136018145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-30DOI: 10.1088/1361-6463/ad005f
Yu Tian, Quanliang Cao
Abstract A comprehensive understanding of the capture process involving matrices in high gradient magnetic separation (HGMS) is crucial for the design and improvement of matrix performance. However, few existing studies have paid attention to the influence of the number of magnetic matrices on the capture process. In this work, we numerically investigate this issue in both longitudinal and transversal HGMS systems, where multiple scenarios with different particle sizes, flow rates and matrix spacing are considered. Interestingly, we show that in most cases, increasing the number of magnetic matrices along the flow direction has little to no influence on the capture radius. It has a certain effect on improving the capture radius only in a few specific cases, such as when dealing with large particles at low flow rates with closely spaced matrices or when working with small particles at high flow rates with widely spaced matrices. These phenomena are related to the appearance of repulsive magnetic forces around matrices and the distribution characteristics of magnetic forces. The obtained results indicate that, in the design of the practical HGMS system, simply increasing the number of matrices along the flow direction may not be a reasonable or effective strategy for enhancing capture performance.
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Pub Date : 2023-10-30DOI: 10.1088/1361-6463/ad039d
Madhumita Bhaumik, Arjun Maity, Hendrik G. Brink, Zolile Wiseman Dlamini, SrinivasuVijaya Vallabhapurapu
Abstract Hybrid nanocomposite (NC) materials comprising organic polymers and inorganic metal nanoparticles (NPs) with unique properties are popular for their advanced technological applications including resistive switching memory devices. Herein, NCs of 2-naphthalene sulphonic acid-doped polyaniline nanotubes (PANI-NSA NTs) and nickel nanoparticles (Ni NPs) were synthesized via a facile chemical synthesis procedure where metallic Ni NPs were embedded in/deposited onto the surface of PANI-NSA NTs by a simple reduction method. Different characterization methods revealed successful deposition of weak ferromagnetic Ni NPs onto the PANI-NSA matrix. The bipolar resistive switching behaviour of the as-synthesized PANI-NSA + Ni NCs was investigated under the application of voltage stress in a two-terminal sandwiched device configuration. The fabricated indium tin oxide/PANI-NSA + Ni/silver (ITO/PANI-NSA + Ni/Ag) device displays bipolar resistive switching properties having a memory window of ∼1.5 × 10 3 , and switches effectively over 200 cycles. Ohmic conduction in the lower-voltage regime and the space-charge-limited Mott–Gurney current conduction model in the higher-voltage region were identified as major charge conduction mechanisms in the high resistive state of the device. On the other hand, in the entire low resistive state region the experimental data followed the Mott–Gurney conduction model.
{"title":"Resistive switching behaviour of nickel nanoparticles embedded naphthalene sulfonic acid doped polyaniline nanocomposites","authors":"Madhumita Bhaumik, Arjun Maity, Hendrik G. Brink, Zolile Wiseman Dlamini, SrinivasuVijaya Vallabhapurapu","doi":"10.1088/1361-6463/ad039d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad039d","url":null,"abstract":"Abstract Hybrid nanocomposite (NC) materials comprising organic polymers and inorganic metal nanoparticles (NPs) with unique properties are popular for their advanced technological applications including resistive switching memory devices. Herein, NCs of 2-naphthalene sulphonic acid-doped polyaniline nanotubes (PANI-NSA NTs) and nickel nanoparticles (Ni NPs) were synthesized via a facile chemical synthesis procedure where metallic Ni NPs were embedded in/deposited onto the surface of PANI-NSA NTs by a simple reduction method. Different characterization methods revealed successful deposition of weak ferromagnetic Ni NPs onto the PANI-NSA matrix. The bipolar resistive switching behaviour of the as-synthesized PANI-NSA + Ni NCs was investigated under the application of voltage stress in a two-terminal sandwiched device configuration. The fabricated indium tin oxide/PANI-NSA + Ni/silver (ITO/PANI-NSA + Ni/Ag) device displays bipolar resistive switching properties having a memory window of ∼1.5 × 10 3 , and switches effectively over 200 cycles. Ohmic conduction in the lower-voltage regime and the space-charge-limited Mott–Gurney current conduction model in the higher-voltage region were identified as major charge conduction mechanisms in the high resistive state of the device. On the other hand, in the entire low resistive state region the experimental data followed the Mott–Gurney conduction model.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"22 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136019239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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