Liquid Phase Epitaxy of Ferromagnetic-Piezoelectrics Heterostructures and Femto-Tesla Magnetic Sensors and Arrays

铁磁压电异质结构和飞特斯拉磁传感器和阵列的液相外延

• 批准号: 1307714
• 负责人: Gopalan Srinivasan
• 金额: $ 34.5万
• 依托单位: Oakland University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1307714&HistoricalAwards=false
• 关键词: Liquid; Phase; Epitaxy; Ferromagnetic; Piezoelectrics

A research program is proposed on novel piezoelectric-ferromagnetic heterostructures for miniature, low-frequency, femto-Tesla magnetic sensors and sensor arrays with potential for applications in biomedical imaging. A majority of such magneto-electric (ME) composites studied so far have bonded ferroelectric and ferromagnetic layers in which an applied ac magnetic field produces magnetostrictive strain in the ferromagnet, leading to a voltage response in the ferroelectric layer. Ferroelectrics based ME sensors have several shortcomings including non-linear sensor response and considerable noise due to ferroelectric hysteresis and pyroelectric noise. This proposal is aimed at magnetic sensors made of piezoelectric lanthanum gallium tantalate, La3Ga5.5Ta0.5O14 (LGT), and functionally graded ferromagnetic layer with nickel zinc ferrite Ni1-xZnxFe2O4 (NZFO). The motivation is the group's preliminary data on ME effects in LGT-ferromagnetic composites that show (i) one to two orders of magnitude higher ME coefficients at low-frequency and at bending and electromechanical resonance, and much lower noise compared to samples with ferroelectrics, and (ii) theoretical models that predict a strong zero-bias ME interactions in the heterostructures. Intellectual Merit:The novelty in the planned approach is multifold with: (i) use of piezoelectric LGT that is expected to show strong ME coupling, linear voltage response to ac magnetic field and elimination of pyroelectric noise, (ii) graded ferromagnetic layers for self-magnetic biasing; (iii) heterostructures by liquid phase epitaxy (LPE) for efficient strain transfer; and (iv) utilization of micro-electro-mechanical systems (MEMS) technology in miniaturization of sensors and sensor arrays. Primary tasks will include (i) synthesis of magnetization-graded NZFO films on LGT substrates by liquid-phase epitaxy (LPE), (ii) studies on low-frequency and resonance ME interactions, (iii) design and fabrication of MEMS cantilever based ferrite/LGT multiple structures as resonant frequency tunable magnetic sensors and sensor array, (iv) comprehensive characterization of the materials and sensors. The desired fT-sensitivity will be achieved by frequency modulation with the sensor operating at bending or electromechanical resonance. Broader Impacts:Anticipated broader impacts of the research include the following: (i) Miniature magnetic sensors and sensor arrays for applications in diverse fields, including medical imaging (magneto-cardiography and magneto-encephalography) and security systems. (ii) Human resources development and curriculum development/enrichment in materials and measurement technologies. (iii) Undergraduate Research Training: The PIs will recruit undergraduate science and engineering majors for participation in the research. (iv) Research experience for high school students: Students from local schools will be recruited for participation in research.

提出了一种新型压电-铁磁异质结构的研究方案，用于小型、低频、飞秒特斯拉磁传感器和传感器阵列，具有在生物医学成像中应用的潜力。 大多数这样的磁电（ME）复合材料研究到目前为止，结合铁电和铁磁层，其中施加的交流磁场产生磁致伸缩应变的铁磁体，导致在铁电层的电压响应。 基于铁电体的ME传感器具有几个缺点，包括非线性传感器响应和由于铁电滞后和热释电噪声引起的相当大的噪声。该提议针对由压电钽酸镧镓La3Ga5.5Ta0.5O14（LGT）和具有镍锌铁氧体Ni 1-xZnxFe 2 O 4（NZFO）的功能梯度铁磁层制成的磁传感器。 其动机是该小组关于LGT-铁磁复合材料中ME效应的初步数据，这些数据显示（i）与铁电体样品相比，低频和弯曲和机电谐振时的ME系数高出一到两个数量级，并且噪声低得多，以及（ii）预测异质结构中强零偏压ME相互作用的理论模型。智力优点：计划方法的新奇是多方面的：（一）使用压电LGT，预计将显示出强ME耦合，线性电压响应交流磁场和消除热电噪声，（二）梯度铁磁层的自磁偏置;（三）异质结构的液相外延（LPE）有效的应变转移;以及（iv）在传感器和传感器阵列的小型化中利用微机电系统（MEMS）技术。 主要任务将包括（i）通过液相外延（LPE）在LGT衬底上合成磁化梯度NZFO薄膜，（ii）研究低频和谐振ME相互作用，（iii）设计和制造MEMS悬臂梁铁氧体/LGT多重结构作为谐振频率可调磁传感器和传感器阵列，（iv）材料和传感器的综合表征。所需的fT灵敏度将通过频率调制来实现，其中传感器在弯曲或机电谐振下操作。 更广泛的影响：预计这项研究的更广泛影响包括：㈠微型磁传感器和传感器阵列，用于不同领域，包括医学成像（心磁图和脑磁图）和安全系统。(ii)人力资源开发和课程开发/材料和测量技术的丰富。(iii)本科生研究培训：PI将招募本科理工专业学生参与研究。(iv)高中生的研究经验：将招募当地学校的学生参加研究。