Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO（001） films is investigated by magnetoresistance measurements. When the temperature decreases from 300K to 80K, the measured three-...Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO（001） films is investigated by magnetoresistance measurements. When the temperature decreases from 300K to 80K, the measured three-jump hysteresis loops turn into two-jump loops. The temperature dependence of the fourfold in-plane magnetic anisotropy constant K1, domain wall pinning energy, and an additional uniaxial magnetic anisotropy constant KUare responsible for this transformation. The strengths of K1 and domain wall pinning energy increase with decreasing temperature, but KU remains unchanged. Moreover, magnetization reversal mechanisms, with either two successive or two separate 90°domain wall propagation, are introduced to explain the multi-jump magnetic switching process in epitaxial Fe/MgO（001） films at different temperatures.展开更多
This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loo...This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.展开更多
We consider the asymptotic property of the diffusion processes with Markovian switching. For a general case, we prove a large deviation principle for empirical measures of switching diffusion processes with small para...We consider the asymptotic property of the diffusion processes with Markovian switching. For a general case, we prove a large deviation principle for empirical measures of switching diffusion processes with small parameters.展开更多
We express a photonic packet switch prototype based on optical label processing methods which dramatically increase the label processing capability. We experimentally demonstrate 40Gbit/s/port packet switching and opt...We express a photonic packet switch prototype based on optical label processing methods which dramatically increase the label processing capability. We experimentally demonstrate 40Gbit/s/port packet switching and optical buffering capabilities of the prototype.展开更多
In recent years,the unique mechanism of sliding ferroelectricity with ultralow switching barriers has been experimentally verified in a series of 2-dimensional(2D)materials.However,its practical applications are hinde...In recent years,the unique mechanism of sliding ferroelectricity with ultralow switching barriers has been experimentally verified in a series of 2-dimensional(2D)materials.However,its practical applications are hindered by the low polarizations,the challenges in synthesis of ferroelectric phases limited in specific stacking configurations,and the low density for data storage since the switching process involves large-area simultaneous sliding of a whole layer.Herein,through first-principles calculations,we propose a type of semi-sliding ferroelectricity in the single metal porphyrin molecule intercalated in 2D bilayers.An enhanced vertical polarization can be formed independent on stacking configurations and switched via sliding of the molecule accompanied by the vertical displacements of its metal ion anchored from the upper layer to the lower layer.Such semi-sliding ferroelectricity enables each molecule to store 1 bit data independently,and the density for data storage can be greatly enhanced.When the bilayer exhibits intralayer ferromagnetism and interlayer antiferromagnetic coupling,a considerable difference in Curie temperature between 2 layers and a switchable net magnetization can be formed due to the vertical polarization.At a certain range of temperature,the exchange of paramagnetic-ferromagnetic phases between 2 layers is accompanied by ferroelectric switching,leading to a hitherto unreported type of multiferroic coupling that is long-sought for efficient"magnetic reading+electric writing".展开更多
基金supported by the National Basic Research Program of China(Grant Nos.2015CB921403,2011CB921801,and 2012CB933102)the National Natural Science Foundation of China(Grant Nos.51427801,11374350,and 11274361)
文摘Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO（001） films is investigated by magnetoresistance measurements. When the temperature decreases from 300K to 80K, the measured three-jump hysteresis loops turn into two-jump loops. The temperature dependence of the fourfold in-plane magnetic anisotropy constant K1, domain wall pinning energy, and an additional uniaxial magnetic anisotropy constant KUare responsible for this transformation. The strengths of K1 and domain wall pinning energy increase with decreasing temperature, but KU remains unchanged. Moreover, magnetization reversal mechanisms, with either two successive or two separate 90°domain wall propagation, are introduced to explain the multi-jump magnetic switching process in epitaxial Fe/MgO（001） films at different temperatures.
基金financially supported by the Russian Science Foundation Grant No.24-22-00063,https:/rscf.ru/project/24-22-00063/at the Southern Federal University.
文摘This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.
基金The authors would like to thank the referees for providing many helpful comments and suggestions. Research of the second author was supported in part by the National Natural Science Foundation of China （Grant No. 11171024）.
文摘We consider the asymptotic property of the diffusion processes with Markovian switching. For a general case, we prove a large deviation principle for empirical measures of switching diffusion processes with small parameters.
文摘We express a photonic packet switch prototype based on optical label processing methods which dramatically increase the label processing capability. We experimentally demonstrate 40Gbit/s/port packet switching and optical buffering capabilities of the prototype.
基金supported by the National Natural Science Foundation of China under contract nos.1210040567 and 22073034the Fundamental Research Funds of Zhejiang Sci-Tech University under contract no.20062320-Y.
文摘In recent years,the unique mechanism of sliding ferroelectricity with ultralow switching barriers has been experimentally verified in a series of 2-dimensional(2D)materials.However,its practical applications are hindered by the low polarizations,the challenges in synthesis of ferroelectric phases limited in specific stacking configurations,and the low density for data storage since the switching process involves large-area simultaneous sliding of a whole layer.Herein,through first-principles calculations,we propose a type of semi-sliding ferroelectricity in the single metal porphyrin molecule intercalated in 2D bilayers.An enhanced vertical polarization can be formed independent on stacking configurations and switched via sliding of the molecule accompanied by the vertical displacements of its metal ion anchored from the upper layer to the lower layer.Such semi-sliding ferroelectricity enables each molecule to store 1 bit data independently,and the density for data storage can be greatly enhanced.When the bilayer exhibits intralayer ferromagnetism and interlayer antiferromagnetic coupling,a considerable difference in Curie temperature between 2 layers and a switchable net magnetization can be formed due to the vertical polarization.At a certain range of temperature,the exchange of paramagnetic-ferromagnetic phases between 2 layers is accompanied by ferroelectric switching,leading to a hitherto unreported type of multiferroic coupling that is long-sought for efficient"magnetic reading+electric writing".
