For Fe layers covered by two-dimensional arrays of hexagonal close-packed polystyrene spheres which are hemispherically covered by Au films on the top,fine structures are observed in reflection,magneto-optical Kerr ro...For Fe layers covered by two-dimensional arrays of hexagonal close-packed polystyrene spheres which are hemispherically covered by Au films on the top,fine structures are observed in reflection,magneto-optical Kerr rotation and ellipticity spectra.The Kerr rotation achieves peaks or exhibits a narrow resonance-like spectral lineshape near the reflection minima,depending on the mechanism of the reflection dips.The Kerr rotation peaks and the resonance-like lineshape both are shifted with the sphere diameters.These phenomena can be attributed to the excitation of surface plasmon resonance and Fabry–Pérot modes.展开更多
Magnetic and magneto-transport properties of nano-structured CoO-Ag granular films are reported.Apparent magnetization hysteresis is observed for low CoO contents and becomes weaker with increasing CoO content.Magneto...Magnetic and magneto-transport properties of nano-structured CoO-Ag granular films are reported.Apparent magnetization hysteresis is observed for low CoO contents and becomes weaker with increasing CoO content.Magnetoresistance (MR) ratio has a maximal value near 84vol% CoO and is reduced at low CoO contents.It decreases with increasing temperature and disappears near the Néel temperature of CoO.The uncompensated magnetic moments of CoO particles have been clearly demonstrated by MR effect.展开更多
Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (...Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (hcp) structure with preferred [100] orientation along the nanowire axis and a face-centered cubic (fcc) structure with preferred [220] orientation,respectively.With increasing growth voltage,the room-temperature coercivity along the nanowire axis is enhanced gradually.For fcc Co nanowires,the coercivity increases monotonically with increasing temperature while for hcp Co nanowires,a minimal coercivity is obtained along both parallel-to-axis and perpendicular-to-axis orientations with the temperature rising from 50K to 390K.The abnormal temperature dependence of the coercivity can be attributed to the competition between the shape anisotropy and magnetocrystalline anisotropy as a function of temperature.展开更多
Measurements of magnetization precession are performed for L2_(1) and B2−ordered Co_(2)FeAl_(0.5)Si_(0.5) full Heusler alloy films using the time−resolved magneto-optical Kerr effect technique in the out-of-plan confi...Measurements of magnetization precession are performed for L2_(1) and B2−ordered Co_(2)FeAl_(0.5)Si_(0.5) full Heusler alloy films using the time−resolved magneto-optical Kerr effect technique in the out-of-plan configuration.Dependence of the precession frequency on the external magnetic field can be fitted by the Landau–Lifshitz–Gilbert equation.The chirp parameters are close to each other for the L2_(1) and B2 structures,and decrease with the external magnetic field increasing.The relaxation rate of the B2−ordered film is smaller than that of the L2_(1) one.展开更多
The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresist...The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresistance ratioΔR/R was found to be enhanced by 2-7 times comparing with the single layer granular films.The enhancement was explained by the antiferromagnetic coupling due to magnetostatic interaction between the Co clusters in neighboring magnetic layers.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 51171129,10974032the National Basic Research Program of China under Grant No 2009CB929201Shanghai Committee of Science and Technology under Grant No 11JC1412700。
文摘For Fe layers covered by two-dimensional arrays of hexagonal close-packed polystyrene spheres which are hemispherically covered by Au films on the top,fine structures are observed in reflection,magneto-optical Kerr rotation and ellipticity spectra.The Kerr rotation achieves peaks or exhibits a narrow resonance-like spectral lineshape near the reflection minima,depending on the mechanism of the reflection dips.The Kerr rotation peaks and the resonance-like lineshape both are shifted with the sphere diameters.These phenomena can be attributed to the excitation of surface plasmon resonance and Fabry–Pérot modes.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50871030,10974032 and 51171129the National Basic Research Program of China under Grant No 2009CB929201.
文摘Magnetic and magneto-transport properties of nano-structured CoO-Ag granular films are reported.Apparent magnetization hysteresis is observed for low CoO contents and becomes weaker with increasing CoO content.Magnetoresistance (MR) ratio has a maximal value near 84vol% CoO and is reduced at low CoO contents.It decreases with increasing temperature and disappears near the Néel temperature of CoO.The uncompensated magnetic moments of CoO particles have been clearly demonstrated by MR effect.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074112 and 10974032the National Basic Research Program of China under Grant Nos 2009CB929201 and 2010CB923401+1 种基金the Key Project of the Ministry of Education of China under Grant No 210074the Innovation Program of Shanghai Municipal Education Commission(No 10ZZ117).
文摘Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (hcp) structure with preferred [100] orientation along the nanowire axis and a face-centered cubic (fcc) structure with preferred [220] orientation,respectively.With increasing growth voltage,the room-temperature coercivity along the nanowire axis is enhanced gradually.For fcc Co nanowires,the coercivity increases monotonically with increasing temperature while for hcp Co nanowires,a minimal coercivity is obtained along both parallel-to-axis and perpendicular-to-axis orientations with the temperature rising from 50K to 390K.The abnormal temperature dependence of the coercivity can be attributed to the competition between the shape anisotropy and magnetocrystalline anisotropy as a function of temperature.
基金by the National Natural Science Foundation of China under Grant Nos 10874247,50871030 and 10974032the National Basic Research Program of China under Grant No 2009CB929201.
文摘Measurements of magnetization precession are performed for L2_(1) and B2−ordered Co_(2)FeAl_(0.5)Si_(0.5) full Heusler alloy films using the time−resolved magneto-optical Kerr effect technique in the out-of-plan configuration.Dependence of the precession frequency on the external magnetic field can be fitted by the Landau–Lifshitz–Gilbert equation.The chirp parameters are close to each other for the L2_(1) and B2 structures,and decrease with the external magnetic field increasing.The relaxation rate of the B2−ordered film is smaller than that of the L2_(1) one.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19754001 and 59392800,and Shanghai Research Center for Applied Physics.
文摘The dependence of giant magnetoresistance of sputtered granular type(Co-Ag)/Ag multilayers on the thickness of Ag layers and magnetic layers with varying Co content in the magnetic layers was studied.The magnetoresistance ratioΔR/R was found to be enhanced by 2-7 times comparing with the single layer granular films.The enhancement was explained by the antiferromagnetic coupling due to magnetostatic interaction between the Co clusters in neighboring magnetic layers.
