Based on Smith-Beljers theory and classical laminate theory, an explicit model is proposed for the ferromagnetic resonance （FMR） frequency shift of a stress-mediumed laminated magnetoelectric structure tuned by an e...Based on Smith-Beljers theory and classical laminate theory, an explicit model is proposed for the ferromagnetic resonance （FMR） frequency shift of a stress-mediumed laminated magnetoelectric structure tuned by an electric field. This model can effectively predict the experimental phenomenon that the FMR frequency increases under a parallel magnetic field and decreases under a perpendicular magnetic field when the electric field ranges from - 10 kV/m to 10 kV/m. Besides, this theory further shows that the FMR frequency increases monotonically as the angle between the direction of the external magnetic field and the outside normal direction of the laminated structure increases, and the frequency will increase as great as 7 GHz. In addition, when the angle reaches a certain critical value, the external electric field fails to tune the FMR frequency. When the angle is above the critical value, the increase of the electric field induces the FMR frequency to increase, and the opposite scenario happens when it is below the critical value. When the angle is 90~ （parallel magnetic field）, the FMR frequency is the most sensitive to the change of the electric field.展开更多
The low Gilbert damping factor, which is usually measured by ferromagnetic resonance, is crucial in spintronic applications. Two-magnon scattering occurs when the orthogonMity of the ferromagnetic resonance mode and o...The low Gilbert damping factor, which is usually measured by ferromagnetic resonance, is crucial in spintronic applications. Two-magnon scattering occurs when the orthogonMity of the ferromagnetic resonance mode and other degenerate spin wave modes was broken by magnetic anisotropy, voids, second phase, surface defects, etc., which is important in analysis of ferromagnetic resonance linewidth. Direct fitting to linewidth with Gilbert damping is advisable only when the measured linewidth is a linear function of measuring frequency in a broad band measurement. We observe the nonlinear ferromagnetic resonance linewidth of Co2MnSi thin films with respect to measuring frequency in broad band measurement. Experimental data could be well fitted with the model including two-magnon scattering with no fixed parameters. The fitting results show that two-magnon scattering results in the nonlinear linewidth behavior, and the Gilbert damping factor is much smaller than reported ones, indicating that our Co2MnSi films are more suitable for the applications of spin transfer torque.展开更多
Low-temperature fired ferrites or ceramics are usually processed by using low-melting materials(e.g.,glasses,oxides,and eutectics)as sintering aids to obtain compact and uniform microstructures.Herein,a dual-strategy ...Low-temperature fired ferrites or ceramics are usually processed by using low-melting materials(e.g.,glasses,oxides,and eutectics)as sintering aids to obtain compact and uniform microstructures.Herein,a dual-strategy of co-doping with V_(2)O_(5)and Sb_(2)O_(3)oxides and forming a eutectic liquid phase has been employed to reduce the melting point of LiZn ferrite ceramics in an effective way.The results indicate that miniscule amounts of V_(2)O_(5)and Sb_(2)O_(3)co-doping contribute in producing dense and uniform microstructures with enhanced magnetic performance by low-temperature firing.The phase structural and microstructural evolutions have been studied in detail.Thereafter their correlations with magnetic properties have been revealed.Enhanced magnetic performance(B_(s)=475.4 mT,M_(s)=82.51 emu/g,B_(r)/B_(s)=0.85,H_(c)=2.2 Oe,ΔH=153.8 Oe)of the LiZn-based ferrite ceramics is achieved by optimized composition and microstructure,which shows great potential for microwave applications including phase shifters and radars.More importantly,such a co-doping strategy can be also extended to other material systems,like dielectric ceramics,hexagonal ferrites or piezoelectric ceramics.展开更多
Detailed mathematical modelling approaches that are used to describe the dynamic behaviour of magnetoelectric coupling in magnetostrictive-piezoelectric multiferroics at low-frequencies, in electromechanical resonance...Detailed mathematical modelling approaches that are used to describe the dynamic behaviour of magnetoelectric coupling in magnetostrictive-piezoelectric multiferroics at low-frequencies, in electromechanical resonance region and at microwave range are discussed. The ME （magnetoelectric） voltage coefficients were estimated from the known material parameters. The feasibility for creating new class of functional devices based on magnetoelectric interactions is addressed.展开更多
Fragile X (Fra (X)) syndrome is the most frequent cause of inherited mentalretardation, and it is associated with the fragile site at Xq27.3. In 1991, the FMR1(fragile X mental retardation 1) gene was cloned in the vi...Fragile X (Fra (X)) syndrome is the most frequent cause of inherited mentalretardation, and it is associated with the fragile site at Xq27.3. In 1991, the FMR1(fragile X mental retardation 1) gene was cloned in the vicinity of this site. The muationand abnormal expression of FMR1 are the direct causes of Fra(X) syndrome. The展开更多
Fragile X syndrome （FXS） is the most common cause of inherited intellectual disability and the most common known genetic cause of autism or autism spectrum disorders. FXS is caused by silencing or mutation of the fr...Fragile X syndrome （FXS） is the most common cause of inherited intellectual disability and the most common known genetic cause of autism or autism spectrum disorders. FXS is caused by silencing or mutation of the fragile X mental retardation gene （FMR1）, a known RNA-binding protein that acts as a negative regulator of translation [1, 2]. FXS patients demonstrate a myriad of symptoms that can vary widely between individuals, including impaired cognition, physical abnormalities, sleep problems, hyperarousal to sensory stimuli, increased anxiety, obsessive compulsive disorder-like behavior, attention-deficit hyperactive disorder symptoms, self-injurious behavior, aggression, and increased risk of seizures [3]. The molecular mechanisms underlying FXS are not clear, and currently there is no ideal treatment.展开更多
Tensile-strained epitaxial La0.67Ba0.33MnO3(LBMO)film has been prepared by magnetron sputtering technique on(001)oriented spinel MgAl2O4substrate.The transport and magnetic measurements give an insulator-metal transit...Tensile-strained epitaxial La0.67Ba0.33MnO3(LBMO)film has been prepared by magnetron sputtering technique on(001)oriented spinel MgAl2O4substrate.The transport and magnetic measurements give an insulator-metal transition and paramagnetic-ferromagnetic transition occurring at^150 K and 250 K respectively,which implies the phase separation in such a tensile-strained film.By analyzing the angular and temperature dependences of the ferromagnetic resonance(FMR),we determine the magnetocrystalline anisotropy of the film.It is found that the tensile-strained film is dominated by an easy-axis corresponding to the compressive out-of-plane direction,though the magnitudes of anisotropy constants are relatively small and their temperature dependences are some complex.Furthermore,the FMR spectra show additional spin wave resonance(SWR),and the field positions can be indexed to follow a linear dependence on the square of index n.The scaling gives a spin-wave exchange stiffness D of 20.7 meV 2at low temperature,which is less than half of that in strain-free LBMO films,implying that the double exchange interaction is remarkably suppressed in the tensile-strained LBMO films.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10802082 and 11172285)the Natural Science Foundation of Zhejiang Province of China(Grant No.LR13A020002)the China Postdoctoral Science Foundation(Grant Nos.20100480089 and 201104727)
文摘Based on Smith-Beljers theory and classical laminate theory, an explicit model is proposed for the ferromagnetic resonance （FMR） frequency shift of a stress-mediumed laminated magnetoelectric structure tuned by an electric field. This model can effectively predict the experimental phenomenon that the FMR frequency increases under a parallel magnetic field and decreases under a perpendicular magnetic field when the electric field ranges from - 10 kV/m to 10 kV/m. Besides, this theory further shows that the FMR frequency increases monotonically as the angle between the direction of the external magnetic field and the outside normal direction of the laminated structure increases, and the frequency will increase as great as 7 GHz. In addition, when the angle reaches a certain critical value, the external electric field fails to tune the FMR frequency. When the angle is above the critical value, the increase of the electric field induces the FMR frequency to increase, and the opposite scenario happens when it is below the critical value. When the angle is 90~ （parallel magnetic field）, the FMR frequency is the most sensitive to the change of the electric field.
基金Supported by the National Basic Research Program of China under Grant No 2015CB921502the National Natural Science Foundation of China under Grant Nos 11474184 and 11174183+4 种基金the Program for New Century Excellent Talents of China under Grant No NCET-10-0541the Scientific Research Foundation for Returned Overseas Chinese Scholars under Grant No B13029the Natural Science Foundation of Shandong Province under Grant No JQ201201the Doctorate Foundation of Shandong Province under Grant No BS2013CL042the Young Scientists Fund of the National Natural Science Foundation of China under Grant No 11204164
文摘The low Gilbert damping factor, which is usually measured by ferromagnetic resonance, is crucial in spintronic applications. Two-magnon scattering occurs when the orthogonMity of the ferromagnetic resonance mode and other degenerate spin wave modes was broken by magnetic anisotropy, voids, second phase, surface defects, etc., which is important in analysis of ferromagnetic resonance linewidth. Direct fitting to linewidth with Gilbert damping is advisable only when the measured linewidth is a linear function of measuring frequency in a broad band measurement. We observe the nonlinear ferromagnetic resonance linewidth of Co2MnSi thin films with respect to measuring frequency in broad band measurement. Experimental data could be well fitted with the model including two-magnon scattering with no fixed parameters. The fitting results show that two-magnon scattering results in the nonlinear linewidth behavior, and the Gilbert damping factor is much smaller than reported ones, indicating that our Co2MnSi films are more suitable for the applications of spin transfer torque.
基金partly supported by“Double First-Rate of China”the National Natural Science Foundation of China(grant no.61734002)+1 种基金“the Fundamental Research Funds for Central Universities”(grant no.20826041D4125)the Sichuan Science and Technology Program(grant nos.2020JDR0016 and 2020ZDZX0008)
文摘Low-temperature fired ferrites or ceramics are usually processed by using low-melting materials(e.g.,glasses,oxides,and eutectics)as sintering aids to obtain compact and uniform microstructures.Herein,a dual-strategy of co-doping with V_(2)O_(5)and Sb_(2)O_(3)oxides and forming a eutectic liquid phase has been employed to reduce the melting point of LiZn ferrite ceramics in an effective way.The results indicate that miniscule amounts of V_(2)O_(5)and Sb_(2)O_(3)co-doping contribute in producing dense and uniform microstructures with enhanced magnetic performance by low-temperature firing.The phase structural and microstructural evolutions have been studied in detail.Thereafter their correlations with magnetic properties have been revealed.Enhanced magnetic performance(B_(s)=475.4 mT,M_(s)=82.51 emu/g,B_(r)/B_(s)=0.85,H_(c)=2.2 Oe,ΔH=153.8 Oe)of the LiZn-based ferrite ceramics is achieved by optimized composition and microstructure,which shows great potential for microwave applications including phase shifters and radars.More importantly,such a co-doping strategy can be also extended to other material systems,like dielectric ceramics,hexagonal ferrites or piezoelectric ceramics.
文摘Detailed mathematical modelling approaches that are used to describe the dynamic behaviour of magnetoelectric coupling in magnetostrictive-piezoelectric multiferroics at low-frequencies, in electromechanical resonance region and at microwave range are discussed. The ME （magnetoelectric） voltage coefficients were estimated from the known material parameters. The feasibility for creating new class of functional devices based on magnetoelectric interactions is addressed.
基金Project supported by the State Education Commission and the National Natural Science Foundation of China.
文摘Fragile X (Fra (X)) syndrome is the most frequent cause of inherited mentalretardation, and it is associated with the fragile site at Xq27.3. In 1991, the FMR1(fragile X mental retardation 1) gene was cloned in the vicinity of this site. The muationand abnormal expression of FMR1 are the direct causes of Fra(X) syndrome. The
基金supported by grants from the National Natural Science Foundation of China(31471125 and 31671215)the‘‘One Thousand Talents Plan of China’’
文摘Fragile X syndrome （FXS） is the most common cause of inherited intellectual disability and the most common known genetic cause of autism or autism spectrum disorders. FXS is caused by silencing or mutation of the fragile X mental retardation gene （FMR1）, a known RNA-binding protein that acts as a negative regulator of translation [1, 2]. FXS patients demonstrate a myriad of symptoms that can vary widely between individuals, including impaired cognition, physical abnormalities, sleep problems, hyperarousal to sensory stimuli, increased anxiety, obsessive compulsive disorder-like behavior, attention-deficit hyperactive disorder symptoms, self-injurious behavior, aggression, and increased risk of seizures [3]. The molecular mechanisms underlying FXS are not clear, and currently there is no ideal treatment.
基金supported by the National Natural Science Foundation of China (11174261)
文摘Tensile-strained epitaxial La0.67Ba0.33MnO3(LBMO)film has been prepared by magnetron sputtering technique on(001)oriented spinel MgAl2O4substrate.The transport and magnetic measurements give an insulator-metal transition and paramagnetic-ferromagnetic transition occurring at^150 K and 250 K respectively,which implies the phase separation in such a tensile-strained film.By analyzing the angular and temperature dependences of the ferromagnetic resonance(FMR),we determine the magnetocrystalline anisotropy of the film.It is found that the tensile-strained film is dominated by an easy-axis corresponding to the compressive out-of-plane direction,though the magnitudes of anisotropy constants are relatively small and their temperature dependences are some complex.Furthermore,the FMR spectra show additional spin wave resonance(SWR),and the field positions can be indexed to follow a linear dependence on the square of index n.The scaling gives a spin-wave exchange stiffness D of 20.7 meV 2at low temperature,which is less than half of that in strain-free LBMO films,implying that the double exchange interaction is remarkably suppressed in the tensile-strained LBMO films.
