CoxCu100-x granular films were prepared by electro deposition(ED).The relationship between Co concentration and ED potential, as well as the influence of ED and annealing conditions on GMR have been studied. It is fou...CoxCu100-x granular films were prepared by electro deposition(ED).The relationship between Co concentration and ED potential, as well as the influence of ED and annealing conditions on GMR have been studied. It is found that the maximum value of GMR depends on the annealing temperature and Co concentration. After annealing Co16Cu84 sample at 425 ℃, we got the maximum value of GMR with -5 %at room temperature, 1100 kA·m-1and -10% at 77 K, 650 kA·m-1. TEM measurement was used to study the microstructure and the explanation of explain the results.展开更多
介绍了一种基于巨磁电阻材料(G ian t m agnetores istance,GM R)为传感器的电子指南针。由于GM R磁场灵敏度高、易集成、能耗低以及成本低,其潜力明显优于磁通门、磁感应和霍尔效应等其他传感器。本文以GM R为传感器,构筑了水平状态下...介绍了一种基于巨磁电阻材料(G ian t m agnetores istance,GM R)为传感器的电子指南针。由于GM R磁场灵敏度高、易集成、能耗低以及成本低,其潜力明显优于磁通门、磁感应和霍尔效应等其他传感器。本文以GM R为传感器,构筑了水平状态下的电子指南针,精度达到±1;°并在系统中采用加速度计,分析了非水平状态下所产生的误差。展开更多
Granular CoxCu1-x alloy films were prepared by electrodeposition at room temperature directly onto semiconducting Si substrate. X-ray diffraction (XRD) revealed that the as-deposited films formed single phase metastab...Granular CoxCu1-x alloy films were prepared by electrodeposition at room temperature directly onto semiconducting Si substrate. X-ray diffraction (XRD) revealed that the as-deposited films formed single phase metastable fcc alloy structure. The fcc lattice parameter α was found to decrease linearly with increasing Co concentration x in the studied range. The giant magnetoresistance (GMR) of the films was improved after annealing. Pure Co fcc diffraction peaks were observed in the diffractogram of the annealed sample, indicating phase separation occurred upon annealing. The optimal annealing temperature was 450℃. The maximum of magnetoresistance (MR) ratio 8.21% was obtained for the Co20Cu80 thin film after annealing at 450℃ for 1 h. The saturation field decreased upon annealing in the MR curves of Co20Cu80 film.展开更多
The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance （SV-GMR） in nanoscale were investigated experimentally and theoretically by nanosized magnet...The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance （SV-GMR） in nanoscale were investigated experimentally and theoretically by nanosized magnetic simulation methods. Based on the Landau-Lifshitz-Gilbert equation, a model with a special gridding was proposed to calculate the giant magnetoresistance ratio （MR） and investigate the magnetization reversal mode. The relationship between MR and the external magnetic field was obtained and analyzed. Studies into the variation of the magnetization distribution reveal that the magnetization reversal mode, that is, the jump variation mode for NiFe/Cu/CoFe/IrMn, depends greatly on the antiferromagnetic coupling behavior between the pinned layer and the antiferromagnetic layer. It is also found that the switching field is almost linear with the exchange coefficient.展开更多
The structure and microfabrication,the detecting theory and the way of biomolecular recognition device based on giant magnetoresistance(GMR) effect are introduced,also the signal detecting and processing instrumentati...The structure and microfabrication,the detecting theory and the way of biomolecular recognition device based on giant magnetoresistance(GMR) effect are introduced,also the signal detecting and processing instrumentation are presented. Here the GMR biosensor was fabricated with magnetic tunnel junction(MJT) material.The biomolecular recognition device contains an array of MJT sensors,single MJT sensor size is 10μm×20μm,tunneling magnetoresistance ratio(TMR) at room temperature is 52.2%,the typical values of junction resistance-area product Rs is 2.6 kΩμm^2,detecting sensitivity of this system is about 8×10^(-4) A·m^(-1).Bioadaptation layer of this device was fabricated with PDMS the thickness of which is less than 100 nm.展开更多
The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respec...The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respectively.GMR （giant magnetoresistance） ratio of the film with/without Co ion implantation was measured. The results showed that Co ion implantation decreased the granule size of the annealed multilayer film, and increased Hc value and GMR ratio of the multilayer film. After annealing at 360℃, the multilayer film [NiFeCo（10 nm）/Ag（10 nm）]×20 with/without Co ion implantation both exhibited the highest GMR ratio of 12.4%/11% under 79.6 kA/m of applied saturation magnetic field.展开更多
A phenomenological theoretical model for magnetic multilayer based on Boltzmann equation and Fuchs-Sondheimer theory is studied. An oscillatory transmission coefficient (Ts) is introduced into the boundary conditions ...A phenomenological theoretical model for magnetic multilayer based on Boltzmann equation and Fuchs-Sondheimer theory is studied. An oscillatory transmission coefficient (Ts) is introduced into the boundary conditions to simulate the alternate ferromagnetic and anti-ferromagnetic coupling between the magnetic layers. The transmission coefficient has an oscillatory factor relating to the thickness of space layer. Other effects such as interface roughness on Ts are also taken into account. The numerical results for [Fe/Cr]n multilayer agree with the experimental data very well, both in the period and range of osciallation, which is leaded by the dependence of giant magnetoresistance(GMR) on layer thickness of space layer.展开更多
文摘CoxCu100-x granular films were prepared by electro deposition(ED).The relationship between Co concentration and ED potential, as well as the influence of ED and annealing conditions on GMR have been studied. It is found that the maximum value of GMR depends on the annealing temperature and Co concentration. After annealing Co16Cu84 sample at 425 ℃, we got the maximum value of GMR with -5 %at room temperature, 1100 kA·m-1and -10% at 77 K, 650 kA·m-1. TEM measurement was used to study the microstructure and the explanation of explain the results.
文摘介绍了一种基于巨磁电阻材料(G ian t m agnetores istance,GM R)为传感器的电子指南针。由于GM R磁场灵敏度高、易集成、能耗低以及成本低,其潜力明显优于磁通门、磁感应和霍尔效应等其他传感器。本文以GM R为传感器,构筑了水平状态下的电子指南针,精度达到±1;°并在系统中采用加速度计,分析了非水平状态下所产生的误差。
基金This work was supported by the National Natural Science Foundation of China under grant No.50071039,50271046supported by the United Academy of Education Ministry,Tianjin University and Nankai University.
文摘Granular CoxCu1-x alloy films were prepared by electrodeposition at room temperature directly onto semiconducting Si substrate. X-ray diffraction (XRD) revealed that the as-deposited films formed single phase metastable fcc alloy structure. The fcc lattice parameter α was found to decrease linearly with increasing Co concentration x in the studied range. The giant magnetoresistance (GMR) of the films was improved after annealing. Pure Co fcc diffraction peaks were observed in the diffractogram of the annealed sample, indicating phase separation occurred upon annealing. The optimal annealing temperature was 450℃. The maximum of magnetoresistance (MR) ratio 8.21% was obtained for the Co20Cu80 thin film after annealing at 450℃ for 1 h. The saturation field decreased upon annealing in the MR curves of Co20Cu80 film.
基金financially supported by the National Natural Science Foundation of China (Nos. 61025021and 60936002)the National Key Project of Scienceand Technology of China (Nos. 2009ZX02023-001-3 and 2011ZX02403-002)the Independent Scientific Research of Tsinghua University (No. 2010THZ0)
文摘The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance （SV-GMR） in nanoscale were investigated experimentally and theoretically by nanosized magnetic simulation methods. Based on the Landau-Lifshitz-Gilbert equation, a model with a special gridding was proposed to calculate the giant magnetoresistance ratio （MR） and investigate the magnetization reversal mode. The relationship between MR and the external magnetic field was obtained and analyzed. Studies into the variation of the magnetization distribution reveal that the magnetization reversal mode, that is, the jump variation mode for NiFe/Cu/CoFe/IrMn, depends greatly on the antiferromagnetic coupling behavior between the pinned layer and the antiferromagnetic layer. It is also found that the switching field is almost linear with the exchange coefficient.
文摘The structure and microfabrication,the detecting theory and the way of biomolecular recognition device based on giant magnetoresistance(GMR) effect are introduced,also the signal detecting and processing instrumentation are presented. Here the GMR biosensor was fabricated with magnetic tunnel junction(MJT) material.The biomolecular recognition device contains an array of MJT sensors,single MJT sensor size is 10μm×20μm,tunneling magnetoresistance ratio(TMR) at room temperature is 52.2%,the typical values of junction resistance-area product Rs is 2.6 kΩμm^2,detecting sensitivity of this system is about 8×10^(-4) A·m^(-1).Bioadaptation layer of this device was fabricated with PDMS the thickness of which is less than 100 nm.
基金support by the National Natural Science Foundation of China under grant No.59771026.
文摘The composition, phase structure and microstructure of the discontinuous multilayer film[NiFeCo（10 nm）/Ag（10 nm）]×20 were investigated after Co ion implantation and annealing at 280, 320,360 and 400℃, respectively.GMR （giant magnetoresistance） ratio of the film with/without Co ion implantation was measured. The results showed that Co ion implantation decreased the granule size of the annealed multilayer film, and increased Hc value and GMR ratio of the multilayer film. After annealing at 360℃, the multilayer film [NiFeCo（10 nm）/Ag（10 nm）]×20 with/without Co ion implantation both exhibited the highest GMR ratio of 12.4%/11% under 79.6 kA/m of applied saturation magnetic field.
文摘A phenomenological theoretical model for magnetic multilayer based on Boltzmann equation and Fuchs-Sondheimer theory is studied. An oscillatory transmission coefficient (Ts) is introduced into the boundary conditions to simulate the alternate ferromagnetic and anti-ferromagnetic coupling between the magnetic layers. The transmission coefficient has an oscillatory factor relating to the thickness of space layer. Other effects such as interface roughness on Ts are also taken into account. The numerical results for [Fe/Cr]n multilayer agree with the experimental data very well, both in the period and range of osciallation, which is leaded by the dependence of giant magnetoresistance(GMR) on layer thickness of space layer.
