A5034105411- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- Semiconductor Quantum Structures and Devices
- Superconducting Materials and Applications
- Advanced Condensed Matter Physics
- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Terahertz technology and applications
- Superconducting and THz Device Technology
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Magnetic Properties and Applications
- Rare-earth and actinide compounds
- Iron-based superconductors research
- Dielectric materials and actuators
- Thermal Expansion and Ionic Conductivity
- Superconductivity in MgB2 and Alloys
- Inorganic Chemistry and Materials
- Seismic Waves and Analysis
- Structural Health Monitoring Techniques
- Spectroscopy and Laser Applications
- Solidification and crystal growth phenomena
- Advanced Electrical Measurement Techniques
- Advanced Chemical Physics Studies
Second Affiliated Hospital of Dalian Medical University
2025
Dalian Medical University
2025
Guilin University of Technology
2024
Nanjing University
2004-2024
Collaborative Innovation Center of Advanced Microstructures
1991-2024
Sun Yat-sen University
2020
National Institute for Materials Science
2014-2017
Institute of Electronics
2014
We have combined a stand-alone Bi2Sr2CaCu2O8 intrinsic Josephson junction stack, emitting terahertz radiation, with YBa2Cu3O7 grain boundary acting as detector. The detector is mounted on lens, positioned 1.2 cm away from the emitter similar lens. With radiating at 0.5 THz, we observed up to 7 Shapiro steps current-voltage characteristic of ac current induced in this was 0.9 mA, and dissipated power 1.8 μW. setup, although far being optimized, may be considered first step towards an...
We report on Bi2Sr2CaCu2O8 (BSCCO) intrinsic Josephson junction stacks with improved cooling, allowing for a remarkable increase in emission frequency compared to the previous designs. started BSCCO stack embedded between two gold layers. When mounted standard way single substrate, emits range of 0.43–0.82 THz. then glued second, thermally anchored substrate onto sample surface. The maximum voltage this better cooled and dimension-unchanged was increased and, accordingly, both frequencies...
Developing a tunable source of high-power terahertz radiation is an ongoing research challenge, with promise for applications including biosensing and high-speed communication. The authors show that the THz emission from stack intrinsic Josephson junctions in cuprate superconductor embedded between two gold layers can be manipulated by focused laser beam. output power increased as much 75% irradiation, tuned continuously rapidly beam moved along length stack, locally heating different spots sample.
Sources of terahertz radiation (between the far infrared and microwave frequencies) are in high demand for a host applications. The authors report on what is essentially ``T-ray flashlight'', compact portable source tunable, continuous light, employing stack intrinsic Josephson junctions cuprate superconductor as emitter. This economical convenient device can be driven by one everyday 1.5-V battery, should facilitate airport security, nondestructive evaluation, remote detection trace gases,...
Recently, it has been found that, when operated at large input power, the linewidth $\ensuremath{\Delta}f$ of terahertz radiation emitted from intrinsic Josephson junction stacks can be as narrow some megahertz. In this high-bias regime, a hot spot coexists with regions which are still superconducting. Surprisingly, was to decrease increasing bath temperature. We present simple model describing dynamics stack in presence by two parallel arrays pointlike junctions and an additional shunt...
We used one-dimensional coupled sine-Gordon equations combined with heat diffusion to numerically investigate the thermal and electromagnetic properties of a $300\,\mu\mathrm{m}$ long intrinsic Josephson junction stack consisting $N = 700$ junctions. The junctions in are $M$ segments where we assume that inside segment all behave identically. Most simulations for $M 20$. For not too high bath temperatures there is appearence hot spot at bias currents. In terms properties, robust standing...
We used 2D coupled sine-Gordon equations combined with 3D heat diffusion to numerically investigate the thermal and electromagnetic properties of a $250 \times 70\,\mu\mathrm{m}^2$ intrinsic Josephson junction stack. The 700 junctions are grouped 20 segments; we assume that in segment all behave identically. At large input power hot spot forms Resonant modes, oscillating either along length ((0, $n$) modes) or width (($m$, 0) stack having more complex structure, can be excited both without...
Acoustic measurements from 10-2 to 107 Hz show that phase-like transitions (PLTs) characterized by a small jump of lattice parameters in the range 100-300 K always exist high-Tc (near 100 K) superconducting Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O. Ferroelastic loops associated with elastic softening C'=((C11+C22)/2-C12)/2 C66 invariably occur at PLT temperatures, some cases shape memory effect may be observed. For various samples Tl-Ba-Ca-Cu-O different Tc, acoustic attenuation (Q-1,...
For various samples of Bi-Sr-Ca-Cu-O (2:2:2:3 phase, 2:2:1:2 and 2:2:2:3-2:2:1:2 mixed phases) Tl-Ba-Ca-Cu-O phase) with different ${\mathit{T}}_{\mathit{c}}$, the internal friction (${\mathit{Q}}^{\mathrm{\ensuremath{-}}1}$) in kHz range reveals a plateau (${\mathit{Q}}_{\mathit{p}}^{\mathrm{\ensuremath{-}}1}$) above ${\mathit{T}}_{\mathit{c}}$ drops drastically below turning point at ${\mathit{T}}_{\mathit{c}}$. This kind anomaly has not been observed for nonsuperconducting samples. The...
In the present work, a new strategy for preparing authentic two-way shape memory polymer was proposed by using conventional crosslinked polyurethane (PU) containing crystalline poly(ε-caprolactone) (PCL) as proof-ofconcept material.Lauroyl peroxide (LPO) added chemical crosslinker inducing secondary crosslinking during programming.Having been stretched and heat treated without additional ingredients chemicals, trained PU showed desired effect.The network created LPO successfully converted...
We report on the investigation of electrothermal behavior and terahertz (THz) emission properties two nearby Bi2Sr2CaCu2O (BSCCO) intrinsic Josephson junction stacks, using a combination electric transport THz measurements plus low temperature scanning laser microscopy. start with compact BSCCO stack (placed in z-shaped structure between electrodes) lateral dimensions height, consisting about 480 junctions. After characterization, 200 nm wide slit was introduced by focused ion beam milling,...
The internal friction of partially Sr-substituted Y(Ba1-xSrx)2Cu3O7-δ (Y123) ceramics was measured by the vibrating-reed method from liquid nitrogen temperature to room at kilohertz frequencies. intensity peak, which appears around 220 K, decreases upon Sr doping while peak position shows no systematic change. Our results do not support previous oxygen order-disorder explanation; we present another approach relating this crossover in charge-carrier dynamics, and its evolution with is...
We report ${}^{63,65}\mathrm{Cu}$ nuclear quadrupole resonance (NQR) spectra of Sr-substituted $\mathrm{Y}({\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{)}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ at room temperature. The chemical pressure effect associated with Sr substitution leads to the results that planar Cu(2) NQR signals are shifted higher frequencies and chain Cu(1) lower frequencies. With substitution, linewidths increase significantly for both...
We report on doping and undoping experiments of terahertz (THz) emitting intrinsic Josephson junction stacks, where the change in charge carrier concentration is achieved by heavy current injection. The were performed stand-alone structures fabricated from a Bi2Sr2CaCu2O single crystal near optimal doping. stacks contained about 930 junctions. On purpose, over only modest range concentrations, changing critical temperature stack less than 1 K. show that both feasible also for large used THz...
Hexagonal manganites can exhibit the low-symmetry ferroelectric (FE) P63cm and partially undistorted anti-ferroelectric (PUA) P-3c1 states. The two states are accompanied by distinct sixfold vortex domain structures. transition from FE PUA (FE-PUA transition) is an effective means to control structures with properties, which of rich physical properties potential applications. FE-PUA only be achieved doping Ga on Mn site InMnO3, but actual path associated structure evolution still unclear....
The mechanical relaxation spectra of a superconducting and nonsuperconducting MgC 1-x Ni 3 samples were measured from liquid nitrogen temperature to room at frequency kilohertz.There are two internal friction peaks (at 300 K labeled as P1 125 P2) for the sample.For non-superconducting one, position shifts 250 K, while P2 is almost completely depressed.It found that peak towards higher under measuring frequency.The calculated activation energy 0.13eV.We propose an explanation relating carbon...
A ceramic sample of Y Ba2Cu4O8 (Y124) was synthesized at atmospheric pressure with the addition NaNO3 as an enhancer. The internal friction measured from liquid nitrogen temperature to room kilohertz frequency using vibrating reed method. Instead a broad peak around 220 K observed in Ba2Cu3O7−δ (Y123) small step spectrum 200 increase Y124. This behaviour is similar that Sr-substituted Ba0.8Sr1.2Cu3O7−δ. We expect Y124 originates charge carrier crossover. size change due suppression lattice...
Although the dynamics of domain growth has been a long-standing topic in ferroic systems, its science complexity and important guidance to practical applications cannot be overemphasized. Highly anisotropic systems with only domain-wall-type defects roughly isotropic vortex-type have extensively studied as two ideal extreme examples terms dynamics. The processes these types are believed follow different scaling laws. driving forces behind wall motion vortex–antivortex annihilation,...
The internal friction of Ca partially substituted Y1−xCaxBa2Cu3O7−δ ceramics was measured using the vibrating reed method from liquid-nitrogen temperature to room at kilohertz frequency. There are two thermally activated relaxation peaks (called P1 and P2 95 K 120 K, respectively). intensity almost remains unchanged with substitution, while that decreases. Another peak appears around 220 P3). With increase content, P3 decreases position shifts toward low temperature. We also have observed Zn...