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A magnetoelectric effect based pico -Tesla-resolution ( DC ) magnetometer. 指导教师:冯志华 教授 学 生:王洪波 SA10009038 201 1 年 11 月 16 日. 1. 2. 3. 4. 5. Background. Advances in Magnetometer. Physical theory & Experimental. Problems. Result & Discussion.
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A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer 指导教师:冯志华 教授 学 生:王洪波 SA10009038 2011年11月16日
1 2 3 4 5 Background Advances in Magnetometer Physical theory & Experimental Problems Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer
1 Background A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • 磁场测量的意义 生物医学研究 空间科学探测 地磁研究 矿物勘探 导航、定位 状态监测 各类传感器 ... ...
1 Background A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic field density (B) 磁感应强度(B)的大小: 人造强磁场脉冲记录:97.5T(2011) 一般人造磁体:0.01T~2T 超导体产生的磁场:10~20T 地磁场:40~60 uT (地磁场每天的变化约为25nT,几秒内的波动约为1nT) 地磁的空间分布:0.02nT/m (北美) 心脏磁场:几十至上百pT 脑 磁场:pT级 ------------------------------------------ 通1mA电流的无限长直导线在1m处产生的磁场为0.2nT,在距离100m的地方产生的磁场为2pT。 而现在最好的低温SQUID磁场计的分辨率可达fT级。(最为广泛应用的磁通门一般为10~100pT)
1 Background A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic Sensor
2 Advances in Magnetometer A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • SERF Atomic Magnetometer Nature Vol422, April 10 ,2003 A subfemtotesla multichannel atomic magnetometer @28~54Hz Theoretical limits sensitivity below: 0.01in 1
2 Advances in Magnetometer A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer Chip-scale atomic magnetometer APPLIED PHYSICS LETTERS, VOLUME 85, NUMBER 26,(2004)
2 Advances in Magnetometer A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer Ultrahigh sensitivity magnetic field and magnetization measurements with an atomic magnetometer 0.45 APPLIED PHYSICS LETTERS 97, 151110 (2010)
2 Advances in Magnetometer A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • 各类磁场传感器的对比
2 Advances in Magnetometer A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer Detection of pico-Tesla magnetic fields using magneto-electric sensors at room temperature APPLIED PHYSICS LETTERS 88, 062510,(2006)
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic domain theory & Magnetostrictioneffct (磁畴理论与磁致伸缩)
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetostrictioneffct 磁致伸缩效应 坡莫合金1J85 25 ? 坡莫合金1J22 60~100 Dependence of magnetostriction on magnetic field (schematic)
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetoelectric(ME)effect 磁电效应 ME effect in the composites
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetoelectric Sensor 磁致伸缩应变与施加磁场的非线性关系
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic field sensor structure Schematic diagram of the sensor configuration
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Principle of the sensor
3 Physical theory & Experimental A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • DC Magnetic field Measurement system Block diagram of the Circuit system
4 Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • PZT Output to DC bias magnetic field
4 Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • PZT Output to DC bias magnetic field
4 Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • PZT output Vs excited signal frequency
4 Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic field Sensitivity Vs Excited Frequency
4 Result & Discussion A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • 0.5Hz weak magnetic field test with range of 2uT
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Magnetic field shield Environment Magnetic Noise 10nT level (0.1~5Hz) Magnetic field shield Materials 坡莫合金(铁镍合金)、 微晶合金 (外层:饱和磁感应强度高,内层:初始磁导率高)
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Circuit Systems 1、Preamplifier 2、Lock-in Amplifier (DSP) Model 7265 (AMETeK) • 稳定性 软磁材料的剩磁和磁滞回线带来的问题 较强磁场冲击造成传感器的工作点漂移 甚至不工作。 温度的变化造成共振频率的漂移 可以考虑采用闭环系统使传感器输出幅度稳定 在某一个工作点附近,从而提高系统的线性度 范围、有效测量范围大。
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Optimization 进一步提高灵敏度的方法: 1、软磁材料(磁导率大、磁致伸缩系数大)/新型压电材料PMN-PT 2、改进杆的结构,提高磁放大倍数、共振的Q值,共振时的应力分布等 4、在杆上贴多片陶瓷片检测应变,适当选取陶瓷片的数量和大小以及布置方式从而获得最好的输出灵敏度。 5、改变陶瓷片得极化方向,采用d33模式代替d13模式。 …
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • PZT Vs PMN-PT JOURNAL OF APPLIED PHYSICS 109, 074507 (2011)
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Other ME magnetometers APPLIED PHYSICS LETTERS 99, 153502 (2011)
5 Problems & Optimization A magnetoelectric effect based pico-Tesla-resolution (DC) magnetometer • Application of ME effect 1、High sensitivity magnetic sensors 2、Power harvesting 3、Current sensors 4、ME transformers 5、ME filter 6、ME phase shifter ……
Thank You ! 指导教师:冯志华 教授 学 生:王洪波 SA10009038 2011年11月16日