Examinando por Autor "Campanella, H."

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Comparative performance of static-mode ferrous MEMS gradiometers fabricated by a three-step DRIE process
(IOP Science Publishing, 2010-05-21) Campanella, H.; Del Real, R. P.; Duch, M.; Guerrero, H.; Esteve, J.; Díaz Michelena, M.; Plaza, J. A.
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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Focused-Ion-Beam-Assisted Magnet Fabrication and Manipulation for Magnetic Field Detection Applications
(ACS Publications, 2009-02-16) Campanella, H.; Del Real, R. P.; Díaz Michelena, M.; Duch, M.; Guerrero, H.; Esteve, J.; Plaza, J. A.
A focused-ion-beam-assisted technique intended for ultrasmall, hard-magnet fabrication has been developed. By means of ion-beam-induced milling and deposition, reduced-size NdFeB magnets were extracted from a macroscopic quarry and bonded to the surface of a thin-film bulk acoustic resonator (FBAR). Electrical characterization of the FBAR before and after bonding of the magnet was carried out, thus observing both a downshifting of the resonance frequency and a reduction of the quality factor of the resonator. The magnetic behavior of the nanomagnet has been confirmed by means of magnetometry measurements based on atomic force microscopy.
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In situ MEMS gradiometer with nanometer-resolution optical detection system
(Elsevier, 2010-04-05) Campanella, H.; Del Real, R. P.; Duch, M.; Serre, C.; Lucas, I.; De Manuel, V.; Guerrero, H.; Esteve, J.; Díaz Michelena, M.; Plaza, J. A.
Mechanically resonant ferromagnetic MEMS sensors intended for magnetic field gradient measurements are presented. Suspended quad-beams with proof mass have been designed to improve their sensitivity and to simplify the detection. Fabricated devices exhibit the compact size of current MEMS technologies and are built within a simple deep-reactive-ion etching-based process. Nanometer-resolution detection based on optical interferometry and signal processing techniques have been employed to find out dynamic-mode transformation factors of 6.25 × 10−3 T/m/Hz with 0.1-Hz resolution. The device performs in situ gradiometry with a single-sensor structure, which represents a technological advance to current-art gradiometers.