We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materia...We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materials at GHz frequency, as well as new approaches to these materials＇ characterization. High frequency magnetic properties of magnetic materials determined by the magnetization dynamics of coherent precession are described by the Landau-Lifshitz-Gitbert equation. However, the complexity of the equation results in a lack of analytically universal information between the high frequency magnetic properties and the magnetization dynamics of coherent precession. Consequently, searching for magnetic materials with higher permeability at higher working frequency is still done case by case.展开更多
NiFe204 （NFO）/ZnO composite nanoparticles with different ZnO components were investigated, which were pre- pared by a simple wet chemical route method. The magnetoelectric coupling between magnetostriction from NFO ...NiFe204 （NFO）/ZnO composite nanoparticles with different ZnO components were investigated, which were pre- pared by a simple wet chemical route method. The magnetoelectric coupling between magnetostriction from NFO and piezoelectricity from ZnO was induced by the surface coating NFO nanoparticles of ZnO layer, NFO/ZnO composite showed ferroelectric properties and the remanent electric polarization reached 0.08 μC/cm. Moreover, the changes of resistance at different room temperatures reached about 2% under 3 T magnetic fields comparing with that of zero mag- netic fields. Furthermore, multiferroic NFO/ZnO resulted in enhancement of microwave absorption due to magnetoelectric coupling.展开更多
The half-metallic Heusler alloy CO_(2)FeSi is an ideal material in spintronic devices due to its higher spin polarization,higher Curie temperature and lower damping parameters.In this work,the dynamic magnetism of CO_...The half-metallic Heusler alloy CO_(2)FeSi is an ideal material in spintronic devices due to its higher spin polarization,higher Curie temperature and lower damping parameters.In this work,the dynamic magnetism of CO_(2)FeSi is modulated by electric field and it is demonstrated that the charge-spin conversion efficiencyξis continuous and controllable by the electric field.We further find an extremely highξin ferromagnetic/ferroelectric(FM/FE)heterostructures,which could be ascribed to interfacial effect in FM/FE interface.Moreover,we investigate that the charge-spin conversion efficiency varies with the electric field in a butterfly-like behavior,which accords with the S–E curve of Pb(Mg_(1/3)Nb_(2/3))O_3-Pb_(0.7)Ti_(0.3)O_(3)(PMN-PT)and could be attributed to strain effect.The modulation of charge-spin conversion efficiency in FM/FE heterostructures via electric field presents a profound potential for next-generation spintronic devices and applications of current-induced magnetization switching.展开更多
We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz...We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz is achieved by pre-magnetizing the CoZr films along different azimuth directions,which can be ascribed to the competition between the uniaxial anisotropy caused by the oblique deposition and the rotatable anisotropy induced by the rotatable stripe domain.Furthermore,the regulating range of resonance frequency for the CoZr film can be adjusted by changing the oblique deposition angle.Our results might be beneficial for the applications of magnetic thin films in microwave devices.展开更多
Fe29Cerl and Fe19Ni81 antidot arrays, with different dimensions, are prepared with the rf magnetron sputtering method onto the porous alumina substrate. The size and shape of antidot arrays are characterized by scanni...Fe29Cerl and Fe19Ni81 antidot arrays, with different dimensions, are prepared with the rf magnetron sputtering method onto the porous alumina substrate. The size and shape of antidot arrays are characterized by scanning electron microscopy. The glancing angle x-ray diffraction patterns of Fe29C071 and FelgNi81 antidot arrays indicate the bcc and fcc structures, respectively. The coercivities of both the alloys show abnormal thickness dependence, which are discussed qualitatively by considering the pinning and the thickness effect to the films.展开更多
Cobalt antidot arrays with different thicknesses are fabricated by rf magnetron sputtering onto porous alumina substrates. Scanning electron microscopy and grazing incidence x-ray diffraction are employed to character...Cobalt antidot arrays with different thicknesses are fabricated by rf magnetron sputtering onto porous alumina substrates. Scanning electron microscopy and grazing incidence x-ray diffraction are employed to characterize the morphology and crystal structure of the antidot array, respectively. The temperature dependence of magnetic properties shows that in the temperature range 5 K-300K, coercivity and squareness increase firstly, reach their maximum values, then decrease. The anomalous temperature dependences of coercivity and squareness are discussed by considering the pinning effect of the antidot and the magnetocrystalline anisotropy.展开更多
基金supported by the National Basic Research Program of China(Grant No.2012CB933101)the National Natural Science Foundation of China(Grant Nos.11034004 and 51371093)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1251)the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20130211130003)
文摘We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materials at GHz frequency, as well as new approaches to these materials＇ characterization. High frequency magnetic properties of magnetic materials determined by the magnetization dynamics of coherent precession are described by the Landau-Lifshitz-Gitbert equation. However, the complexity of the equation results in a lack of analytically universal information between the high frequency magnetic properties and the magnetization dynamics of coherent precession. Consequently, searching for magnetic materials with higher permeability at higher working frequency is still done case by case.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51671099,11374131,and 51501081)
文摘NiFe204 （NFO）/ZnO composite nanoparticles with different ZnO components were investigated, which were pre- pared by a simple wet chemical route method. The magnetoelectric coupling between magnetostriction from NFO and piezoelectricity from ZnO was induced by the surface coating NFO nanoparticles of ZnO layer, NFO/ZnO composite showed ferroelectric properties and the remanent electric polarization reached 0.08 μC/cm. Moreover, the changes of resistance at different room temperatures reached about 2% under 3 T magnetic fields comparing with that of zero mag- netic fields. Furthermore, multiferroic NFO/ZnO resulted in enhancement of microwave absorption due to magnetoelectric coupling.
基金the National Natural Science Foundation of China(Grant No.11974149)the Natural Science Foundation of Gansu Province(Grant No.21JR7RA472)。
文摘The half-metallic Heusler alloy CO_(2)FeSi is an ideal material in spintronic devices due to its higher spin polarization,higher Curie temperature and lower damping parameters.In this work,the dynamic magnetism of CO_(2)FeSi is modulated by electric field and it is demonstrated that the charge-spin conversion efficiencyξis continuous and controllable by the electric field.We further find an extremely highξin ferromagnetic/ferroelectric(FM/FE)heterostructures,which could be ascribed to interfacial effect in FM/FE interface.Moreover,we investigate that the charge-spin conversion efficiency varies with the electric field in a butterfly-like behavior,which accords with the S–E curve of Pb(Mg_(1/3)Nb_(2/3))O_3-Pb_(0.7)Ti_(0.3)O_(3)(PMN-PT)and could be attributed to strain effect.The modulation of charge-spin conversion efficiency in FM/FE heterostructures via electric field presents a profound potential for next-generation spintronic devices and applications of current-induced magnetization switching.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51871117 and 51671099)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT-16R35)the Gansu Provincial Science Foundation for Distinguished Young Scholars,China(Grant No.20JR10RA649).
文摘We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz is achieved by pre-magnetizing the CoZr films along different azimuth directions,which can be ascribed to the competition between the uniaxial anisotropy caused by the oblique deposition and the rotatable anisotropy induced by the rotatable stripe domain.Furthermore,the regulating range of resonance frequency for the CoZr film can be adjusted by changing the oblique deposition angle.Our results might be beneficial for the applications of magnetic thin films in microwave devices.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10404011 and 50401018, and the Project for New Century Excellent Talents （NCET） in University.
文摘Fe29Cerl and Fe19Ni81 antidot arrays, with different dimensions, are prepared with the rf magnetron sputtering method onto the porous alumina substrate. The size and shape of antidot arrays are characterized by scanning electron microscopy. The glancing angle x-ray diffraction patterns of Fe29C071 and FelgNi81 antidot arrays indicate the bcc and fcc structures, respectively. The coercivities of both the alloys show abnormal thickness dependence, which are discussed qualitatively by considering the pinning and the thickness effect to the films.
基金Supported by the Doctorial Start-up Fund of Lanzhou University and the National Natural Science Foundation of China under Grant Nos 10404011 and 50401018.
文摘Cobalt antidot arrays with different thicknesses are fabricated by rf magnetron sputtering onto porous alumina substrates. Scanning electron microscopy and grazing incidence x-ray diffraction are employed to characterize the morphology and crystal structure of the antidot array, respectively. The temperature dependence of magnetic properties shows that in the temperature range 5 K-300K, coercivity and squareness increase firstly, reach their maximum values, then decrease. The anomalous temperature dependences of coercivity and squareness are discussed by considering the pinning effect of the antidot and the magnetocrystalline anisotropy.
