弱磁探测无论是在生物、医学、地质等众多领域都有极为重要的应用。近年来，一种新型的由巨磁阻（GMR）和作为磁放大器的超导环构成的混合式磁传感器因结构简单、性能稳定、灵敏度高（理论预计可以达到fT量级）等优点，在弱磁探测领域具有大规模应用的潜力。本项目使用磁阻效应更加优异的隧道磁电阻（TMR）代替GMR，并通过理论分析与实验相结合的手段，对该类传感器进行研究。具体内容包括：超导磁放大器的放大性能的理论与实验分析；并对传感器的噪声来源、TMR与超导磁放大器之间耦合机理进行探索；在此基础上，研制高质量TMR-超导混合式磁传感器，并研究温度、磁场、工作电流等因素对于器件饱和磁场、灵敏度、低频噪声特性的影响。上述研究工作将为新型高灵敏度磁传感器的探索及生产应用提供理论和实验基础。

The detection of extremely low magnetic signals is very important in the field of biotechnology, medical science, geological exploration and so on. Recently, a new magnetic sensor has been proposed. It is composed by a superconducting flux-to field transformer and a high-sensitivity Giant Magnetoresistive sensor (GMR). There are many advantages of this new magnetic sensor. First, the sensitivity of this mixed sensor can reach few tens of femtotesla. Second, the structure of this mixed sensor is simple and reliable. By replacing the GMR sensor by a Tunnel Magnetoresistance (TMR) sensor, the detection level should reach higher level.This project focus on the research of the TMR-superconductor mixed sensor. Keyelements conclude as follows: theoretical analysis and calculation of the superconducting flux-to-field transformer characteristics, research the performance of the sensitivity and noise level of this new mixed sensor, and the coupling effect between TMR and superconductor. The above research will be very helpful for the exploration of new high sensitive magnetic sensor.