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  • 1
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    Fabrication and characterization of YBa〈sub〉2〈/sub〉Cu〈sub〉3〈/sub〉O〈sub〉7–〈/sub〉〈inline-formula〉〈tex-math id="Z-20210129174424"〉\begin{document}$_{ \delta}$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210129174424.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210129174424.png"/〉〈/alternatives〉〈/inline-formula〉 step-edge Josephson junctions on MgO substrate for high-temperature superconducting quantum interference devices
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2021
    In:  Acta Physica Sinica Vol. 70, No. 3 ( 2021), p. 037401-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 70, No. 3 ( 2021), p. 037401-
    Abstract: The YBa〈sub〉2〈/sub〉Cu〈sub〉3〈/sub〉O〈sub〉7–〈i〉δ〈/i〉〈/sub〉 (YBCO) step-edge Josephson junction on MgO substrate has recently been shown to have important applications in making advanced high-transition temperature (high-〈i〉T〈/i〉〈sub〉C〈/sub〉) superconducting devices such as high-sensitivity superconducting quantum interference device (SQUID), superconducting quantum interference filter, and THz detector. In this paper, we investigate the fabrication and transport properties of YBCO step-edge junction on MgO substrate. By optimizing the two-stage ion beam etching process, steps on MgO (100) substrates are prepared with an edge angle 〈i〉θ〈/i〉 of about 34°. The YBCO step-edge junctions are then fabricated by growing the YBCO thin films with a pulsed laser deposition technique and subsequent traditional photolithography. The resistive transition of the junction shows typical foot structure which is well described by the Ambegaokar-Halperin theory of thermally-activated phase slippage for overdamped Josephson junctions. The voltage-current curves with temperature dropping down to 77 K exhibit resistively shunted junction behavior, and the Josephson critical current density 〈i〉J〈/i〉〈sub〉C〈/sub〉 is shown to follow the 〈inline-formula〉〈tex-math id="Z-20210127094830-1"〉\begin{document}$(T_{\rm C}-T)^2$\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210127094830-1.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210127094830-1.png"/〉〈/alternatives〉〈/inline-formula〉 dependence. At 77 K, the 〈i〉J〈/i〉〈sub〉C〈/sub〉 of the junction reaches 1.4 × 10〈sup〉5〈/sup〉 A/cm〈sup〉2〈/sup〉, significantly higher than the range of 10〈sup〉3〈/sup〉–10〈sup〉4〈/sup〉 A/cm〈sup〉2〈/sup〉 as presented by other investigators for YBCO step-edge junctions on MgO substrate with comparable 〈i〉θ〈/i〉 of 35°–45°. This indicates a rather strong Josephson coupling of the junction, and by invoking the results of YBCO bicrystal junctions showing similar values of 〈i〉J〈/i〉〈sub〉C〈/sub〉, it is tentatively proposed that the presently fabricated junction might be described as an S-s′-S junction with s′ denoting the superconducting region of depressed 〈i〉T〈/i〉〈sub〉C〈/sub〉 in the vicinity of the step edge or as an S-N-S junction with N denoting a very thin non-superconducting layer. By incorporating the MgO-based YBCO step-edge junction, high-〈i〉T〈/i〉〈sub〉C〈/sub〉 radio frequency (RF) SQUID is made. The device shows decent voltage-flux curve and magnetic flux sensitivity of 250 〈inline-formula〉〈tex-math id="Z-20210128093740-1"〉\begin{document}$ \text{μ}\Phi_0/{\rm Hz}^{1/2} $\end{document}〈/tex-math〉〈alternatives〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210128093740-1.jpg"/〉〈graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3-20201291_Z-20210128093740-1.png"/〉〈/alternatives〉〈/inline-formula〉 at 1 kHz and 77 K, comparable to the values reported in the literature. To further improve the RF SQUID performance, efforts could be devoted to optimizing the junction parameters such as the junction 〈i〉J〈/i〉〈sub〉C〈/sub〉. By using the YBCO step-edge junction on MgO substrate, high-〈i〉T〈/i〉〈sub〉C〈/sub〉 direct current SQUID could also be developed, as reported recently by other investigators, to demonstrate the potential of MgO-based step-edge junction in making such a kind of device with superior magnetic flux sensitivity.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.70.20201291
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2021
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  • 2
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    Preparation and dielectric properties of BST films with high tunability
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2011
    In:  Acta Physica Sinica Vol. 60, No. 7 ( 2011), p. 077701-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 60, No. 7 ( 2011), p. 077701-
    Abstract: Six-layer Ba0.6Sr0.4TiO3 (BST) films are prepared by an improved sol-gel method. The effects of various preheating methods on morphology and dielectric properties are studied. XRD results reveal that all BST films preferentially grow along the (110) direction and have cubic perovskite structures, and that preheating can obviously enhance crystallization. XPS results show that the preheating can also decrease surface non-perovskite structure and cause perovskite structure to increase markedly. AFM results display that as the preheating number increases, BST films show significant improvement on morphology with surface roughness reducing. The dielectric property measurement exhibits that tunability is remarkably increased with the increase of preheating number. BST film with all layers preheated shows that its tunability exceeds 55% at 20V bias voltage, while BST film with odd number layers preheated presents a moderate capacitance, lower dielectric loss, approximately 50% tunability at 20V bias voltage and significant increase in figure of merit (FOM) with the bias voltage. The excellent combination of dielectric properties can satisfy the application demand of microwave tunable devices. Also, the relevant mechanism of high tunability is discussed.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.60.077701
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2011
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  • 3
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    Influence of growth temperature on properties of AlGaInN quaternary epilayers
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2009
    In:  Acta Physica Sinica Vol. 58, No. 10 ( 2009), p. 7194-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 58, No. 10 ( 2009), p. 7194-
    Abstract: Aluminum gallium indium nitride（AlGaInN） quaternary epilayers were prepared by metalorganic chemical vapor deposition （MOCVD） on c-plane sapphire （α-Al2O3） substrates. Three samples were grown under different temperatures of 800 ℃，850 ℃ and 900 ℃. It is found that the In composition monotonically decreases with the increasing growth temperature，while the Al composition is nearly invariable. The V-pits appeared when the growth temperature increases to 850 ℃, and the size and density of V-pits drastically decrease and the nucleation of V-pits is passivated when the growth temperature rises to 900 ℃ due to the desorption enhancement of segregated In atoms.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.58.7194
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2009
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  • 4
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    Optical phased array output beam calibration method based on Adam algorithm
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2024
    In:  Acta Physica Sinica Vol. 0, No. 0 ( 2024), p. 0-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 0, No. 0 ( 2024), p. 0-
    Abstract: Optical Phased Array (OPA) technology, as a pivotal component of Laser Detection and Ranging (LiDAR) systems, plays a crucial role in augmenting the application efficiency in fields such as autonomous driving, precision measurement, and remote sensing detection. With the escalating demands for high-resolution imaging, the array size of OPAs is continuously expanding, imposing higher requirements on the calibration precision and efficiency of the output beam. Existing calibration algorithms, such as the Simultaneous Perturbation Stochastic Gradient Descent (SPGD) and the Gerchberg-Saxton (GS) algorithm, often face challenges of prolonged calibration times and insufficient precision when dealing with large-scale OPA systems. Addressing this issue, our study introduces the Adam optimization algorithm, renowned for its adaptive learning rate feature, into the calibration process of OPA output beams for the first time. Through simulation modeling and experimental validation, this research comprehensively examines the performance differences between the Adam algorithm and conventional SPGD and GS algorithms in beam calibration, especially under various OPA array configurations. For a 16×16 OPA array, the application of the Adam algorithm significantly enhances the Peak Side Lobe Ratio (PSLR) to over 15.98dB, while notably reducing the number of iterations to fewer than 600, thereby shortening the calibration cycle and improving calibration precision effectively. Furthermore, this study delves into an in-depth analysis of parameter selection, convergence speed, and stability of the Adam algorithm in OPA calibration, offering detailed guidance for achieving more efficient and higher quality beam calibration. Through comparative analysis, this paper not only demonstrates the substantial advantages of the Adam algorithm in enhancing OPA calibration efficiency, reducing calibration duration, and optimizing output beam quality but also emphasizes its critical role in advancing OPA technology. The primary contribution of this research lies in providing an innovative algorithmic approach for efficient calibration of OPA output beams, which is of significant theoretical and practical importance for the advancement of LiDAR technology, particularly in the realm of high-precision beam control. Moreover, by applying optimized algorithms, this study not only improves the performance of OPA technology within existing domains but also paves new pathways for its application in emerging fields such as optical communications, optical networking, and high-resolution imaging.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Article
    DOI: 10.7498/aps.73.20231772
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2024
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  • 5
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    Fractional spins and fractional statistics of composite Boson field
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2006
    In:  Acta Physica Sinica Vol. 55, No. 5 ( 2006), p. 2149-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 55, No. 5 ( 2006), p. 2149-
    Abstract: The composite Boson fields are quantizated in FS (Faddeev-Senjanovic) path integral quantizated formalism. The fractional spins and fractional statistics is obtained by using the quantum Noether theorem.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.55.2149
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2006
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  • 6
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    Effects of B additive on structure and magnetic properties of Co-Zr-Mo alloys
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2012
    In:  Acta Physica Sinica Vol. 61, No. 20 ( 2012), p. 207501-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 61, No. 20 ( 2012), p. 207501-
    Abstract: The phases and magnetic properties of Co77Zr18-xBxMo5 (x=1.0, 1.5, 2.0, 2.5, and 4.0) are studied by X-ray diffraction analysis and magnetic measurements. Proper addition of Ti could improve the magnetic properties of Co-Zr alloy significantly. The largest value of Hc=7.0 kOe (1 Oe =79.5775 A/m) is obtained in the Co77Zr16Mo5B2 melt-spun ribbon. The grain size of Co5Zr phase decreases with the increase of B content, which contributes significantly to the enhancement of exchange-coupling effect. The coercivity values of the Co77Zr18-xMo5Bx (x=1.0, 1.5, 2.0, 2.5) melt-spun ribbons are affected mainly by the grain size of the Co5Zr phase. The coercivity value first increases and then decreases with the decrease of the Co5Zr phase. On the other hand, the coercivity mechanisms of Co77Zr18-xBxMo5 (x=1.0, 1.5, 2.0, 2.5) melt-spun ribbons are found to be of the pinning type.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.61.207501
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2012
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  • 7
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    Growth mechanism and optoelectronic properties of vanadium oxide films prepared by Sol-Gel
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2013
    In:  Acta Physica Sinica Vol. 62, No. 5 ( 2013), p. 056802-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 62, No. 5 ( 2013), p. 056802-
    Abstract: Vanadium oxide films are prepared by Sol-Gel at different annealing temperatures. Their surface morphologies, valence states, electrical and optical properties are characterized by SEM, XRD, resistance meter, UV-Vis spectrometer and FTIR, respectively. Results reveal that the optimal temperature for producing V2O5 films by Sol-gel is 430 ℃, the organics in the films cannot be decomposed completely below 430 ℃ while the V-O bonds will be broken under a higher temperature (〉430 ℃). The as-prepared vanadium pentoxide films exhibit higher TCR and larger light absorption, so that they are suitable to be used as bolometric materials for uncooled infrared detectors. The growth mechanism of vanadium oxide film prepared by Sol-Gel is also presented in this paper.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Journal
    URL: Article
    DOI: 10.7498/aps
    DOI: 10.7498/aps.62.056802
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2013
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  • 8
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    Preparation and thermoelectric properties of layered Bi〈sub〉1–〈i〉x〈/i〉〈/sub〉Sb〈sub〉〈i〉x〈/i〉〈/sub〉Se nanocrystalline films
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2022
    In:  Acta Physica Sinica Vol. 71, No. 19 ( 2022), p. 197301-
    Details
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 71, No. 19 ( 2022), p. 197301-
    Abstract: 〈sec〉BiSe is found to be a promising near-room-temperature thermoelectric material with higher performance than traditional Bi〈sub〉2〈/sub〉Se〈sub〉3〈/sub〉 due to its ultra-low intrinsic lattice thermal conductivity. In this work, N-type BiSe nanocrystalline thin films with (00l) preferred orientation are first prepared via vacuum thermal evaporation method, and Bi〈sub〉1–〈i〉x〈/i〉〈/sub〉Sb〈i〉〈sub〉x〈/sub〉〈/i〉Se nanocrystalline films with different doping concentrations are obtained by Sb co-evaporation. The phases, morphologies, chemical compositions and valences, lattical vibrations, and electrical properties of these films are characterized. It is found that the Sb dopant successfully enters into the crystal lattice and replaces the Bi site of Bi〈sub〉2〈/sub〉Se〈sub〉3〈/sub〉 quintuple layers and Bi〈sub〉2〈/sub〉 bilayers without selectivity, and the difference of gold properties between Sb atom and Bi atoms leads the carrier concentration to sharply decrease and the Seebeck coefficient in doped BiSe to increase. Meanwhile,〈/sec〉〈sec〉the sizes of nanocrystals in the films decrease and the denser layered structure is formed due to the Sb doping, which is conducive to the carrier transport in the samples, and the in-plane carrier mobility of the films effectively increases from 13.6 cm〈sup〉2〈/sup〉·V〈sup〉–1〈/sup〉·s〈sup〉–1〈/sup〉 (BiSe) to 19.3 cm〈sup〉2〈/sup〉·V〈sup〉–1〈/sup〉·s〈sup〉–1〈/sup〉 (Bi〈sub〉0.65〈/sub〉Sb〈sub〉0.35〈/sub〉Se). The maximum room-temperature power factor of 2.18 μW·cm〈sup〉–1〈/sup〉·K〈sup〉–2〈/sup〉 is obtained in Bi〈sub〉0.76〈/sub〉Sb〈sub〉0.24〈/sub〉Se, which is higher than that in undoped BiSe. The results of this work indicate that the BiSe-based thin films have potential applications in room temperature thermoelectric thin film devices.〈/sec〉
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    URL: Article
    DOI: 10.7498/aps.71.20220834
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2022
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