Hybrid GMR Sensor Detecting 950 pT/sqrt(Hz) at 1 Hz and Room Temperature.

Advances in the magnetic sensing technology have been driven by the increasing demand for the capability of measuring ultrasensitive magnetic fields. Among other emerging applications, the detection of magnetic fields in the picotesla range is crucial for biomedical applications. In this work Picosense reports a millimeter-scale, low-power hybrid magnetoresistive-piezoelectric magnetometer with subnanotesla sensitivity at low frequency. Through an innovative noise-cancelation mechanism, the 1/f noise in the MR sensors is surpassed by the mechanical modulation of the external magnetic fields in the high frequency regime. A modulation efficiency of 13% was obtained enabling a final device's sensitivity of ~950 pT/Hz1/2 at 1 Hz. This hybrid device proved to be capable of measuring biomagnetic signals generated in the heart in an unshielded environment. This result paves the way for the development of a portable, contactless, low-cost and low-power magnetocardiography device

Magnetically tunable visible reflectivity utilizing the electron accumulation in indium-tin-oxide waveguide layer with subwavelength grating

Magnetic field detection was experimentally demonstrated utilizing the optical spectral change of Al-subwavelength grating (SWG) on indium-tin-oxide (ITO) layer. The Al-SWG was fabricated on the ITO layer by electron-beam lithography technique. The fabricated sample shows the peak in the reflection spectrum resulting from the excitation of guided-mode in ITO layer. Electron accumulation layer in ITO was induced by applying magnetic field and flowing current, and the accumulation layer decreased the reflection peak intensity. As the magnetic field of 172 mT was applied, the intensity decreasing reached to 3 % of that without magnetic field. The intensity returned to the original value before measurement when the magnetic field and the current disappeared. These results indicate that our structure can detect tens of mT magnetic field without degaussing

Implementing biosensing based user preference visualisation in architectural spaces

This study delves into the interplay between architectural spaces and human emotions, leveraging the emergent field of neuroarchitecture. It examines the functional and aesthetic influence of architectural design on individual users, with a focus on biosensing data such as brainwave and eye tracking information to understand user preferences.Comment: 20 page

Hybrid GMR Sensor Detecting 950 pT/sqrt(Hz) at 1 Hz and Room Temperature

Advances in the magnetic sensing technology have been driven by the increasing demand for the capability of measuring ultrasensitive magnetic fields. Among other emerging applications, the detection of magnetic fields in the picotesla range is crucial for biomedical applications. In this work Picosense reports a millimeter-scale, low-power hybrid magnetoresistive-piezoelectric magnetometer with subnanotesla sensitivity at low frequency. Through an innovative noise-cancelation mechanism, the 1/f noise in the MR sensors is surpassed by the mechanical modulation of the external magnetic fields in the high frequency regime. A modulation efficiency of 13% was obtained enabling a final device’s sensitivity of ~950 pT/Hz1/2 at 1 Hz. This hybrid device proved to be capable of measuring biomagnetic signals generated in the heart in an unshielded environment. This result paves the way for the development of a portable, contactless, low-cost and low-power magnetocardiography device

Development of a 3-axis MEMS magnetometer based on Lorentz force

Dissertação de mestrado em Physics Engineering, (especialização em Devices, Microsystems and Nanotechnologies)Typical magnetometers found in the magnetic fields research are highly incompatible with the massive MEMS technology industry that has been the object of study in the past years. This aspect leads to the rapid increase in production costs and reliability reduction. Furthermore, most of the magnetometers that are adapted to this technology are highly complex and with little to no adaptation to outer-space research. In this work, a novel single-axis MEMS magnetometer based on the principle of the Lorentz force capable of reading fields in the X or Y direction is designed and simulated with the description of a fabrication method to be used. This magnetometer uses an innovative design for a current-carrying-bar that’s highly adaptable to a variety of scenarios with a low 100Ω current resistance in each of its paths. An amplitude-modulated method is approached through the use of a capacitive-readout system and an off-resonance frequency of operation to achieve the detection baseline of a 1aF capacitive variation at a 20nT magnetic field. This involves the use of various mechanisms to increase the quality factor and reduce the overall stiffness of the device to increase its displacement caused by the Lorentz force. The device is also to be operated at a 500Pa atmosphere to reduce the damping and, at the same time, increase the quality factor. A thermomechanical noise below 3 /√ with a frequency of operation at around 4977 Hz was deemed necessary to adapt the design to another previously designed single-axis MEMS magnetometer capable of reading fields in the Z direction. Various simulation and design tools are used to predetermine the best properties at which the magnetometer will be operated to its highest capabilities. Through these simulations, a 50Hz bandwidth magnetometer, required for spatial research, is achieved with a capacitance variation of 1.37aF at 20nT surpassing the initial requirements. A 1.77 /√ thermomechanical noise is obtained, well below the baseline that was defined for this work. A fabrication layout was developed with all lithography masks designed, and a microfabrication process flow was devised. The microfabrication process run was partially completed and it’s still ongoing.Os magnetómetros típicos encontrados na investigação de campos magnéticos são altamente incompatíveis com a enorme indústria da tecnologia MEMS que tem sido objeto de estudo nos últimos anos. Este aspeto leva ao rápido aumento dos custos de produção e à redução da fiabilidade. Para além disso a maioria dos magnetómetros adaptados a esta tecnologia são altamente complexos e com pouca ou nenhuma adaptação à investigação espacial. Neste trabalho, um novo magnetómetro MEMS de um único eixo baseado no princípio da força de Lorentz capaz de ler campos na direção X ou Y é concebido e simulado com a descrição de um método de fabrico a ser utilizado. Este magnetómetro utiliza um desenho inovador para uma barra condutora que é altamente adaptável a uma variedade de cenários com uma baixa resistência de 100Ω em cada um dos seus caminhos. Um método de modulação em amplitude é abordado através da utilização de um sistema de leitura capacitiva e uma frequência de operação com um desvio da ressonância para alcançar a linha de base de deteção de uma variação capacitiva de 1aF para um campo magnético de 20nT. Isto envolve a utilização de vários mecanismos para aumentar o fator de qualidade e reduzir a rigidez geral do dispositivo para aumentar o deslocamento causado pela força de Lorentz. O dispositivo deve também ser operado a uma atmosfera de 500Pa para reduzir o amortecimento e, ao mesmo tempo, aumentar o factor de qualidade. Um ruído termomecânico inferior a 3 /√ com uma frequência de operação de cerca de 4977 Hz foram consideradas necessárias para adaptar o desenho a outro magnetómetro MEMS de um eixo, previamente concebido, capaz de ler campos na direção Z. Várias ferramentas de simulação e desenho são utilizadas para pré-determinar as melhores propriedades em que o magnetómetro será operado até às suas capacidades mais elevadas. Através destas simulações, um magnetómetro de 50Hz de largura de banda, necessário para a investigação espacial, é alcançado com uma variação de capacidade de 1.37aF a 20nT, ultrapassando os requisitos iniciais. É obtido um ruído termomecânico de 1.77 /√, bem abaixo da linha de base que foi definida para este trabalho. Foi desenvolvido um esquema de fabricação com todas as máscaras litográficas concebidas, e foi concebido um fluxo de processo de microfabricação. A execução do processo de microfabricação foi parcialmente concluída e ainda está em curso.This work was framed in the scope of the Project (Link4S)ustainability - A new generation connectivity system for creation and integration of networks of objects for new sustainability paradigms [POCI-01- 0247-FEDER-046122 | LISBOA-01-0247-FEDER-046122], financed by the Operational Competitiveness and Internationalization Programmes COMPETE 2020 and LISBOA 2020, under the PORTUGAL 2020 Partnership Agreement, and through the European Structural and Investment Funds in the FEDER component

BioMEMS for cardiac tissue monitoring and maturation

Diseases of the heart have been the most common cause of death in the United States since the middle of the 20th century. The development of engineered cardiac tissue over the last three decades has yielded human induced pluripotent stem cell-derived (hiPSC) cardiomyocytes (CMs), microscale “heart-on-a-chip” platforms, optical interrogation techniques, and more. Having spawned its own scientific field, ongoing research promises lofty goals to address the heart disease burden around the world, such as patient-specific disease models, and clinical trials on chip-based platforms. The greatest academic pursuit for engineered cardiac tissues is to increase their maturity, thereby increasing relevance to native adult tissue. Investigation of cardiomyocyte maturity necessitates the development of 3D-tissue compatible techniques for measuring and perturbing cardiac biology with enhanced precision. This dissertation focuses on the development of biological microelectromechanical systems (BioMEMS) for precision measurement and perturbation of cardiac tissue. We discuss three unique approaches to interfacing MEMS-based tools with cardiac biology. The first is a high resolution magnetic sensor, which directly measures the spatial gradient of a magnetic field. This has an ideal application in magnetocardiography (MCG), as the flux of ions during cardiac contractions produces measurable magnetic signals around the tissue and can be leveraged for noncontact diagnosis. The second is a highly functionalized heart-on-a-chip platform, wherein the mechanical contractions of cardiac microtissues can be simultaneously recorded and actuated. Contractile dynamics are leading indicators of maturity in engineered cardiac tissue and mechanical conditioning has shown recent promise as a critical component of cardiac maturation. The third is the imaging of contractile nanostructures in engineered cardiomyocytes at depth in a 3D microtissue. We use small angle X-ray scattering (SAXS) to discern the periodic arrangement of myofilaments in their native 3D environment. We enable a significant structural analysis to provide insight for functional maturation. Enabling these three thrusts required developing two supporting technologies. The first is the engineered control of dynamic second order systems, a foundational element of all our MEMS and magnetic techniques. We demonstrate numerous algorithms to improve settling time or decrease dead-time such that samples with fast temporal effects can be measured. The second is a microscale gluing technique for integrating myriad of materials with MEMS devices, yielding unique sensors and actuators.2022-05-15T00:00:00