In situ MEMS gradiometer with nanometer-resolution optical detection system

Campanella, Humberto; Real, R. P. del; Duch, Marta; Serre, C.; Lucas, I.; Manuel, Víctor; Guerrero, H.; Estéve, J.; Díaz-Michelena, Marina; Plaza, J.A.

doi:10.1016/j.sna.2010.02.007

Cited by 2 publications

(5 citation statements)

References 26 publications

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“…Linearity exhibited in the experiments makes the system suitable as a magnetostatic gradiometer. In a previous work, we found that suspended quad-beams exhibit better dynamic sensitivity [11]. Thus, performances of static-mode and resonant-mode devices have to be analyzed to evaluate the best device for mixed static-dynamic gradiometer applications.…”

Section: Discussionmentioning

confidence: 99%

“…This is explained by the smaller spring constant of cantilevers. On the other hand, suspended structures like beams or membranes are more rigid, which makes them more sensitive to dynamic-mode, resonant applications, due to their higher resonance frequencies [11]. In the present paper, we study both kinds of clamped-free and clamped-clamped devices to check their different sensitivities in static operation.…”

Section: Concept and Sensor Designmentioning

confidence: 99%

“…Cantilever-beam and suspended quad-beam structures of compact size are built within the simple three-step DRIE process and their static performance is compared. Recently, we reported on the dynamic behavior of a resonant quadbeam gradiometer [11]. For this reason, comparison is now carried out with the aim of choosing the best structure for future mixed static-dynamic applications.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparative performance of static-mode ferrous MEMS gradiometers fabricated by a three-step DRIE process

Campanella¹,

Real²,

Duch³

et al. 2010

J. Micromech. Microeng.

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Two MEMS structures-a cantilever beam and a quad-beam-have been designed and fabricated through a three-step deep reactive ion etching (DRIE) process. Devices feature target patterns to align with an external optical detection system and a micromachined cavity to embed an NdFeB hard mini-magnet, thus releasing the stress of structures. Structures are intended for magnetostatic gradient measurements. Induced magnetic fields generate an attracting force on the magnet that deflects the sensor. Deflection is optically detected through nanometer-resolution confocal microscopy. The static-mode sensitivity of up to 1.86 × 10 −4 T m −1 demonstrates that MEMS gradiometers are able to perform in situ gradiometry with a single sensor and miniaturized size. Suitable techniques for integrated detection are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Concept and Sensor Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative performance of static-mode ferrous MEMS gradiometers fabricated by a three-step DRIE process

Campanella¹,

Real²,

Duch³

et al. 2010

J. Micromech. Microeng.

Self Cite

View full text Add to dashboard Cite

show abstract

“…More recently, MEMS gradiometers have been investigated for the same benefits of traditional MEMS technology and the added benefit of reducing interference from the Earth's field by measuring the gradient [20][21][22][23][24] . Here, both the gradient field resolution and spatial resolution (footprint) are important when measuring the positional change of a magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…20 ). Other works have developed socalled single-point gradiometers that do not require the subtraction of two uniform field sensors, circumventing the issues of asymmetry and drift [21][22][23][24] . These works typically integrate permanent magnets and have achieved resolutions in the high mT cm −1 range with large footprints (>1 mm 2 ).…”

Section: Introductionmentioning

confidence: 99%

100 pT/cm single-point MEMS magnetic gradiometer from a commercial accelerometer

et al. 2020

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Magnetic sensing is present in our everyday interactions with consumer electronics and demonstrates the potential for the measurement of extremely weak biomagnetic fields, such as those of the heart and brain. In this work, we leverage the many benefits of microelectromechanical system (MEMS) devices to fabricate a small, low-power, and inexpensive sensor whose resolution is in the range of biomagnetic fields. At present, biomagnetic fields are measured only by expensive mechanisms such as optical pumping and superconducting quantum interference devices (SQUIDs), suggesting a large opportunity for MEMS technology in this work. The prototype fabrication is achieved by assembling micro-objects, including a permanent micromagnet, onto a postrelease commercial MEMS accelerometer using a pick-and-place technique. With this system, we demonstrate a room-temperature MEMS magnetic gradiometer. In air, the sensor's response is linear, with a resolution of 1.1 nT cm −1 , spans over 3 decades of dynamic range to 4.6 µT cm −1 , and is capable of off-resonance measurements at low frequencies. In a 1 mTorr vacuum with 20 dB magnetic shielding, the sensor achieves a 100 pT cm −1 resolution at resonance. This resolution represents a 30-fold improvement compared with that of MEMS magnetometer technology and a 1000-fold improvement compared with that of MEMS gradiometer technology. The sensor is capable of a small spatial resolution with a magnetic sensing element of 0.25 mm along its sensitive axis, a >4-fold improvement compared with that of MEMS gradiometer technology. The calculated noise floor of this platform is 110 fT cm −1 Hz −1/2 , and thus, these devices hold promise for both magnetocardiography (MCG) and magnetoencephalography (MEG) applications.

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In situ MEMS gradiometer with nanometer-resolution optical detection system

Cited by 2 publications

References 26 publications

Comparative performance of static-mode ferrous MEMS gradiometers fabricated by a three-step DRIE process

Comparative performance of static-mode ferrous MEMS gradiometers fabricated by a three-step DRIE process

100 pT/cm single-point MEMS magnetic gradiometer from a commercial accelerometer

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