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Interfacial Magnetic Anisotropy Controlled Spin Pumping in Co60Fe20B20/Pt Stack Co60Fe20B20/Pt 叠层中受界面磁各向异性控制的自旋泵送
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2024-03-30 DOI: 10.1142/s2010324724400010
Mahammad Tahir, Dhananjay Tiwari, Abhishek Juyal, Rohit Medwal, Soumik Mukhopadhyay
{"title":"Interfacial Magnetic Anisotropy Controlled Spin Pumping in Co60Fe20B20/Pt Stack","authors":"Mahammad Tahir, Dhananjay Tiwari, Abhishek Juyal, Rohit Medwal, Soumik Mukhopadhyay","doi":"10.1142/s2010324724400010","DOIUrl":"https://doi.org/10.1142/s2010324724400010","url":null,"abstract":"<p>Controlled spin transport in magnetic stacks is required to realize pure spin current-driven logic and memory devices. The control over the generation and detection of the pure spin current is achieved by tuning the spin to charge conversion efficiency of the heavy metal interfacing with ferromagnets. Here, we demonstrate the direct tunability of spin angular momentum transfer and thereby spin pumping, in CoFeB/Pt stack, with interfacial magnetic anisotropy. The ultra-low thickness of the CoFeB thin film by tilting the magnetization from in-plane to out-of plane direction due to interfacial anisotropy from higher thickness of CoFeB thin film. The ferromagnetic resonance measurements are performed to investigate the magnetic anisotropy and spin pumping in CoFeB/Pt stacks. We clearly observe tunable spin pumping effect in the CoFeB/Pt stacks with varying CoFeB thicknesses. The spin current density, with varying ferromagnetic layer thickness, is found to increase from 1.10<span><math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>MA/m<sup>2</sup> to 2.40<span><math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"><mspace width=\".17em\"></mspace></math></span><span></span>MA/m<sup>2</sup>, with increasing in-plane anisotropy field. Such interfacial anisotropy-controlled generation of pure spin current can potentially lead to next-generation anisotropic spin current-controlled spintronic devices.</p>","PeriodicalId":54319,"journal":{"name":"Spin","volume":"49 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140571671","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}
引用次数: 0
Tunability of Microwave Frequency Using Spin Torque Nano Oscillator by the Generated Oersted Field with Tunable Free Layer 利用自旋扭矩纳米振荡器通过可调谐自由层产生的奥斯特场调谐微波频率
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2024-03-16 DOI: 10.1142/s2010324724500012
H. Bhoomeeswaran, D. Aravinthan, P. Sabareesan
{"title":"Tunability of Microwave Frequency Using Spin Torque Nano Oscillator by the Generated Oersted Field with Tunable Free Layer","authors":"H. Bhoomeeswaran, D. Aravinthan, P. Sabareesan","doi":"10.1142/s2010324724500012","DOIUrl":"https://doi.org/10.1142/s2010324724500012","url":null,"abstract":"&lt;p&gt;The current-induced magnetization precession dynamics provoked by the spin transfer torque (STT) in a spin valve device i.e. tri-layer device (commonly spin torque nano oscillator (STNO)) is investigated numerically by solving the governing Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation. In this study, we have devised an STNO device made of EuO-based ferromagnetic alloy in free and fixed magnetic layers. The copper acts as a nonmagnetic spacer. Here, we have introduced the current induced Oesterd field (CIOF), which is generated when a spin-polarized current passes through the STNO device. In the device, we have tuned the free layer angle &lt;span&gt;&lt;math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; from &lt;span&gt;&lt;math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; to &lt;span&gt;&lt;math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; as an increment of &lt;span&gt;&lt;math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;. For every individual &lt;span&gt;&lt;math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; ranging from &lt;span&gt;&lt;math altimg=\"eq-00006.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; to &lt;span&gt;&lt;math altimg=\"eq-00007.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, the generated Oersted field’s strength can be altered by increasing the STNO device’s diameter. Henceforth, it is apparent that the frequency tunability is achieved in the device for all the values of &lt;span&gt;&lt;math altimg=\"eq-00008.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;. The frequency and power of the device depend entirely on the material’s saturation magnetization, which inherently reflects the current density and coherence of spin-polarized DC. From the results, it is apparent that for a particular &lt;span&gt;&lt;math altimg=\"eq-00009.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, the frequency keeps increasing with the eventual decrease in power when we increase the strength of the Oersted field from 10&lt;span&gt;&lt;math altimg=\"eq-00010.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mspace width=\".17em\"&gt;&lt;/mspace&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;kA/m to 50&lt;span&gt;&lt;math altimg=\"eq-00011.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mspace width=\".17em\"&gt;&lt;/mspace&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;kA/m. By doing so, the maximum frequency can be tuned up to 212&lt;span&gt;&lt;math altimg=\"eq-00012.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mspace width=\".17em\"&gt;&lt;/mspace&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;GHz ","PeriodicalId":54319,"journal":{"name":"Spin","volume":"10 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140201111","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}
引用次数: 0
Monte Carlo Investigation of Dielectric Characteristics in Silicene–Germanene Nanosystem with Junction Connection 具有结点连接的硅-锗纳米系统介电特性的蒙特卡洛研究
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2024-03-07 DOI: 10.1142/s2010324724500024
Z. Fadil, Rajesh Haldhar, Chaitany Jayprakash Raorane, R. El Fdil, S. Karam, Munirah D. Albaqami, P. Rosaiah, Seong Cheol Kim
{"title":"Monte Carlo Investigation of Dielectric Characteristics in Silicene–Germanene Nanosystem with Junction Connection","authors":"Z. Fadil, Rajesh Haldhar, Chaitany Jayprakash Raorane, R. El Fdil, S. Karam, Munirah D. Albaqami, P. Rosaiah, Seong Cheol Kim","doi":"10.1142/s2010324724500024","DOIUrl":"https://doi.org/10.1142/s2010324724500024","url":null,"abstract":"<p>In this study, Monte Carlo investigation delves into the dielectric features of silicene–germanene nanosystem with junction connection. We emphasized the profound influence of physical parameters, coupling between Si–Si and Ge–Ge atoms and temperature, on these dielectric features. Our results highlight the pivotal role of the coupling parameter between Ge atoms in influencing blocking temperatures, underlining the significance of high values for spin and coupling parameters for achieving a high blocking temperature and delaying transitions. Furthermore, our analysis of electric hysteresis loops demonstrates their sensitivity to parameter variations, which can offer valuable insights for nanoelectronics and materials science applications.</p>","PeriodicalId":54319,"journal":{"name":"Spin","volume":"8 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149344","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}
引用次数: 0
Deposition Pressure Dependence on Spin Hall Angle of W Thin Films Grown on NiFe 沉积压力对在镍铁合金上生长的 W 薄膜自旋霍尔角的影响
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2024-02-15 DOI: 10.1142/s2010324723400271
K. Sriram, Yaswanth Sai Pappu, M. S. Devapriya, Jhantu Pradhan, Arabinda Haldar, Chandrasekhar Murapaka
{"title":"Deposition Pressure Dependence on Spin Hall Angle of W Thin Films Grown on NiFe","authors":"K. Sriram, Yaswanth Sai Pappu, M. S. Devapriya, Jhantu Pradhan, Arabinda Haldar, Chandrasekhar Murapaka","doi":"10.1142/s2010324723400271","DOIUrl":"https://doi.org/10.1142/s2010324723400271","url":null,"abstract":"&lt;p&gt;Spin-to-charge conversion and vice versa due to spin-orbit coupling in ferromagnet-heavy metal heterostructure is of paramount interest for developing energy-efficient spintronic devices. Here, we have systematically investigated the effect of Ar deposition pressure (&lt;span&gt;&lt;math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mtext mathvariant=\"normal\"&gt;Ar&lt;/mtext&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; on the tungsten (&lt;i&gt;W&lt;/i&gt;) crystalline phase and extracted spin-dependent transport parameters. X-ray diffraction results show that 10&lt;span&gt;&lt;math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mspace width=\".17em\"&gt;&lt;/mspace&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;nm-thick &lt;i&gt;W&lt;/i&gt; films exhibit a structural phase transition from a mixed phase of &lt;span&gt;&lt;math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mo stretchy=\"false\"&gt;(&lt;/mo&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-&lt;i&gt;W&lt;/i&gt; to a single phase of &lt;span&gt;&lt;math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-&lt;i&gt;W&lt;/i&gt; as a function of &lt;span&gt;&lt;math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mtext mathvariant=\"normal\"&gt;Ar&lt;/mtext&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;. The observed phase transition is due to a decrease in adatom’s energy and surface mobility. Interestingly, only the &lt;span&gt;&lt;math altimg=\"eq-00006.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mo stretchy=\"false\"&gt;(&lt;/mo&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-&lt;i&gt;W&lt;/i&gt; phase is found to stabilize when &lt;i&gt;W&lt;/i&gt; sputtered on a seed Ni&lt;span&gt;&lt;math altimg=\"eq-00007.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;Fe&lt;span&gt;&lt;math altimg=\"eq-00008.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; (Permalloy or Py) film. The growth of &lt;span&gt;&lt;math altimg=\"eq-00009.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mo stretchy=\"false\"&gt;(&lt;/mo&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-&lt;i&gt;W&lt;/i&gt; on the seed Py layer could be due to the strain that facilitates the mixed phase. &lt;i&gt;W&lt;/i&gt; deposited on the Py layer is shown to be dependent on &lt;span&gt;&lt;math altimg=\"eq-00010.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mtext mathvariant=\"normal\"&gt;Ar&lt;/mtext&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, in which the &lt;span&gt;&lt;math altimg=\"eq-00011.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-&lt;i&gt;W&lt;/i&gt; relative phase fraction is relative. A ferromagnetic resonance (FMR)-based spin pumping method was employed for spin current injection. The FMR linewidth (&lt;span&gt;&lt;math altimg=\"eq-00012.gif\" display=\"inline\" overflow=\"scroll\"","PeriodicalId":54319,"journal":{"name":"Spin","volume":"11 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149346","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}
引用次数: 0
A Micromagnetic Study of the Influences of DMI on Spin-Cherenkov Effect DMI 对自旋-切伦科夫效应影响的微磁研究
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2023-12-15 DOI: 10.1142/s2010324723500340
Mingming Yang, Ming Yan
{"title":"A Micromagnetic Study of the Influences of DMI on Spin-Cherenkov Effect","authors":"Mingming Yang, Ming Yan","doi":"10.1142/s2010324723500340","DOIUrl":"https://doi.org/10.1142/s2010324723500340","url":null,"abstract":"","PeriodicalId":54319,"journal":{"name":"Spin","volume":"43 31","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995856","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}
引用次数: 0
Spin-Orbit Torque and Geometrical Backscattering 自旋轨道转矩和几何反向散射
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2023-12-14 DOI: 10.1142/s2010324723500339
S. G. Tan, Che-Chun Huang, M. Jalil, Ching-Ray Chang, Szu-Cheng Cheng
{"title":"Spin-Orbit Torque and Geometrical Backscattering","authors":"S. G. Tan, Che-Chun Huang, M. Jalil, Ching-Ray Chang, Szu-Cheng Cheng","doi":"10.1142/s2010324723500339","DOIUrl":"https://doi.org/10.1142/s2010324723500339","url":null,"abstract":"","PeriodicalId":54319,"journal":{"name":"Spin","volume":"14 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139002442","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}
引用次数: 0
Testing Connectedness of Images 图像连通性测试
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2023-12-06 DOI: 10.4230/LIPIcs.APPROX/RANDOM.2023.66
Piotr Berman, Meiram Murzabulatov, Sofya Raskhodnikova, Dragos Ristache
{"title":"Testing Connectedness of Images","authors":"Piotr Berman, Meiram Murzabulatov, Sofya Raskhodnikova, Dragos Ristache","doi":"10.4230/LIPIcs.APPROX/RANDOM.2023.66","DOIUrl":"https://doi.org/10.4230/LIPIcs.APPROX/RANDOM.2023.66","url":null,"abstract":"We investigate algorithms for testing whether an image is connected. Given a proximity parameter $epsilonin(0,1)$ and query access to a black-and-white image represented by an $ntimes n$ matrix of Boolean pixel values, a (1-sided error) connectedness tester accepts if the image is connected and rejects with probability at least 2/3 if the image is $epsilon$-far from connected. We show that connectedness can be tested nonadaptively with $O(frac 1{epsilon^2})$ queries and adaptively with $O(frac{1}{epsilon^{3/2}} sqrt{logfrac{1}{epsilon}})$ queries. The best connectedness tester to date, by Berman, Raskhodnikova, and Yaroslavtsev (STOC 2014) had query complexity $O(frac 1{epsilon^2}log frac 1{epsilon})$ and was adaptive. We also prove that every nonadaptive, 1-sided error tester for connectedness must make $Omega(frac 1epsilonlog frac 1epsilon)$ queries.","PeriodicalId":54319,"journal":{"name":"Spin","volume":"13 1","pages":"66:1-66:15"},"PeriodicalIF":1.8,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74529591","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}
引用次数: 0
Upper and Lower Bounds for Complete Linkage in General Metric Spaces 广义度量空间中完全连杆的上界和下界
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2023-11-30 DOI: 10.4230/LIPIcs.APPROX/RANDOM.2021.18
Anna Arutyunova, A. Großwendt, Heiko Röglin, Melanie Schmidt, Julian Wargalla
{"title":"Upper and Lower Bounds for Complete Linkage in General Metric Spaces","authors":"Anna Arutyunova, A. Großwendt, Heiko Röglin, Melanie Schmidt, Julian Wargalla","doi":"10.4230/LIPIcs.APPROX/RANDOM.2021.18","DOIUrl":"https://doi.org/10.4230/LIPIcs.APPROX/RANDOM.2021.18","url":null,"abstract":"In a hierarchical clustering problem the task is to compute a series of mutually compatible clusterings of a finite metric space $$(P,{{,textrm{dist},}})$$ ( P , dist ) . Starting with the clustering where every point forms its own cluster, one iteratively merges two clusters until only one cluster remains. Complete linkage is a well-known and popular algorithm to compute such clusterings: in every step it merges the two clusters whose union has the smallest radius (or diameter) among all currently possible merges. We prove that the radius (or diameter) of every k -clustering computed by complete linkage is at most by factor O ( k ) (or $$O(k^{ln (3)/ln (2)})=O(k^{1{.}59})$$ O ( k ln ( 3 ) / ln ( 2 ) ) = O ( k 1.59 ) ) worse than an optimal k -clustering minimizing the radius (or diameter). Furthermore we give a negative answer to the question proposed by Dasgupta and Long (J Comput Syst Sci 70(4):555–569, 2005. https://doi.org/10.1016/j.jcss.2004.10.006 ), who show a lower bound of $$Omega (log (k))$$ Ω ( log ( k ) ) and ask if the approximation guarantee is in fact $$Theta (log (k))$$ Θ ( log ( k ) ) . We present instances where complete linkage performs poorly in the sense that the k -clustering computed by complete linkage is off by a factor of $$Omega (k)$$ Ω ( k ) from an optimal solution for radius and diameter. We conclude that in general metric spaces complete linkage does not perform asymptotically better than single linkage, merging the two clusters with smallest inter-cluster distance, for which we prove an approximation guarantee of O ( k ).","PeriodicalId":54319,"journal":{"name":"Spin","volume":"27 1","pages":"489-518"},"PeriodicalIF":1.8,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79504194","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}
引用次数: 1
On The Design of Power Attack Immune Spintronic Associative Memory 论功率攻击免疫自旋电子关联存储器的设计
IF 1.8 4区 物理与天体物理
Spin Pub Date : 2023-11-17 DOI: 10.1142/s2010324723500327
Milad Gazanfari, Abdolah Amirany, M. H. Moaiyeri, Kian Jafari
{"title":"On The Design of Power Attack Immune Spintronic Associative Memory","authors":"Milad Gazanfari, Abdolah Amirany, M. H. Moaiyeri, Kian Jafari","doi":"10.1142/s2010324723500327","DOIUrl":"https://doi.org/10.1142/s2010324723500327","url":null,"abstract":"","PeriodicalId":54319,"journal":{"name":"Spin","volume":"38 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266545","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}
引用次数: 0
Phase Diagrams of a Mixed-Spin-1/2 and Spin-5/2 Hexagonal Nanotube with Core-Shell Structure 核壳结构混合自旋1/2和自旋5/2六方纳米管的相图
4区 物理与天体物理
Spin Pub Date : 2023-11-10 DOI: 10.1142/s2010324723500315
R. Aharrouch, Y. Al Qahoom, K. El Kihel, M. Madani, M. El Bouziani
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