FePt （50 nm） and [FePt（a nm）/MgO（b nm）5/glass （a=1, 2, 3; b=1, 2, 3） films were prepared by radio frequency （RF） magnetron sputtering technique, and then were annealed at 600℃ for 30 min. The effect of MgO ...FePt （50 nm） and [FePt（a nm）/MgO（b nm）5/glass （a=1, 2, 3; b=1, 2, 3） films were prepared by radio frequency （RF） magnetron sputtering technique, and then were annealed at 600℃ for 30 min. The effect of MgO layer thickness on the structures and magnetic properties of the FePt/MgO multilayers was investigated. The coercivities and inter-grain interactions of the FePt/MgO films were decreased, yet the degree of （001） texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FePt/MgO films with appropriate coercivities, high perpendicular anisotropy, and weak intergrain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FePt/MgO nanostructured films are promising candidates for future high-density perpendicular recording media.展开更多
Based on the transverse electro-optic effect of lithium niobate crystal,combined with polarizers and Faraday rotator,this paper presents a collinear closed-loop fiber optic current transformer with spatial non-recipro...Based on the transverse electro-optic effect of lithium niobate crystal,combined with polarizers and Faraday rotator,this paper presents a collinear closed-loop fiber optic current transformer with spatial non-reciprocity modulation method,and the feasibility of the scheme is verified by both the theoretical and experimental evidences.The detection scheme avoids the limitation of the transition time of the sensing fiber coil on the phase modulation frequency,improves the sensitivity and stability of the system,and reduces the volume and cost of fiber optic current transformer.The sawtooth wave modulation scheme is adopted to realize phase bias modulation and feedback modulation through phase shift of sawtooth wave to achieve closed-loop detection effect,which enhances the signal to noise ratio and simplifies demodulation mode.The experimental results show that the current ratio errors measured at room temperature range from 1%to 120%of rated current meet the requirements of national standard GB/T 20840.8-2007 and reach the accuracy level of 0.2S.The temperature stability of the current transformer is also tested,and the ratio error measured at the rated current does not exceed±0.2%in the range of-30℃to 50℃.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No.10574085)the Opening Foundation of the Key Laboratory of Shanxi Province (200503010)the Key Project of the Ministry of Education of China (No.207020).
文摘FePt （50 nm） and [FePt（a nm）/MgO（b nm）5/glass （a=1, 2, 3; b=1, 2, 3） films were prepared by radio frequency （RF） magnetron sputtering technique, and then were annealed at 600℃ for 30 min. The effect of MgO layer thickness on the structures and magnetic properties of the FePt/MgO multilayers was investigated. The coercivities and inter-grain interactions of the FePt/MgO films were decreased, yet the degree of （001） texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FePt/MgO films with appropriate coercivities, high perpendicular anisotropy, and weak intergrain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FePt/MgO nanostructured films are promising candidates for future high-density perpendicular recording media.
基金This work was supported by the National Natural Science Foundation of China(Grant No.61735011)the Science and the Key Research and Development Program of Hebei Province(Grant No.19251703D)the Local Science and Technology Development Projects of the Central Committee(Grant No.19941708G).
文摘Based on the transverse electro-optic effect of lithium niobate crystal,combined with polarizers and Faraday rotator,this paper presents a collinear closed-loop fiber optic current transformer with spatial non-reciprocity modulation method,and the feasibility of the scheme is verified by both the theoretical and experimental evidences.The detection scheme avoids the limitation of the transition time of the sensing fiber coil on the phase modulation frequency,improves the sensitivity and stability of the system,and reduces the volume and cost of fiber optic current transformer.The sawtooth wave modulation scheme is adopted to realize phase bias modulation and feedback modulation through phase shift of sawtooth wave to achieve closed-loop detection effect,which enhances the signal to noise ratio and simplifies demodulation mode.The experimental results show that the current ratio errors measured at room temperature range from 1%to 120%of rated current meet the requirements of national standard GB/T 20840.8-2007 and reach the accuracy level of 0.2S.The temperature stability of the current transformer is also tested,and the ratio error measured at the rated current does not exceed±0.2%in the range of-30℃to 50℃.
