Study on a symbiotic combination of the high-Tc superconducting magnetic shield and the ferromagnetic one with magnetic shaking

高温超导磁屏蔽与磁振荡铁磁屏蔽共生组合研究

基本信息

批准号：
03805035
负责人：
SASADA Ichiro
金额：
$ 1.73万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The amplitude of the trapped flux in high-Tc superconductors is strongly affected by the frequency of the magnetic field applied during cooling and the cooling rate. The amplitude is small when the frequency is high or the cooling rate is low.For example,dc magnetic field was trapped in a BiSrCaCuO high-Tc superconducting bulk plate almost as it was;however,ac magnetic field of 10Hz was trapped 1/43 times as small as the amplitude applied to the sample.This nature of the trapped flux allows a new symbiotic combination of ferromagnetic shield with magnetic shaking and high-Tc superconducting magnetic shield.In this combination,the earth's field causing a trapped-flux problem can be attenuated to as small as 0.1mG by the ferromagnetic shield with magnetic shaking whereas any care to suppress the leakage of the shaking field is not needed,making the ferromagnetic shield very thin and lightweight.A miniaturized fluxgate magnetometer(resolution as high as 0.46mG at 77K)is useful to measure the distribution of the trapped flux in high-Tc superconductors,in which,by encapsulating the tip of the core with a piece of copper,the specimen can be avoided to be exposed to high-frequency exciting field of the order of 1G whereas it is transparent to the trapped flux.Amorphous magnetic material(Metglas 2705M)with highly rectangular B-H loop exhibits large enhancement of shielding performance by magnetic shaking which is 20-30 times better than Permally.

高-TC超导体中捕获通量的幅度受到冷却和冷却速率施加的磁场频率的强烈影响。当频率高或冷却速率较低时，振幅很小。例如，将DC磁场捕获在Bisrcacuo高-TC高-TC超导超导板中几乎几乎是如此；但是，10Hz的AC磁场被困在10Hz的AC磁场被困在1/43倍的1/43倍时，将其弹性的弹性和较高的组合型组合起来。超导磁性屏蔽。在这种结合下，造成被困问题的地球场可以通过铁电磁屏蔽层降低至0.1毫克，并具有磁性摇动，而任何护理都不需要抑制摇动场的泄漏，而不需要渗透磁场的渗漏，使得非常薄的盾牌非常薄和轻度速度（使速度较高的速度为速度量高）。为了测量高-TC超导体中被困的通量的分布，其中，通过用一块铜封装核心的尖端，可以避免样品暴露于1G的高频令人兴奋的领域1G的高频领域，而它是透明的，且具有较大的磁性（MetGlas 2705M）的较大磁场（METGLAS 2705M）透明度通过磁性摇动，比正常地好20-30倍。