Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection

In this paper, the impact of Lorentz forces and temperature on the natural frequencies of a piezoresistive sensor composed of two microcantilevers with integrated U-shaped thin-film aluminum heaters are investigated. Two types of experiments were performed. In the first, the sensor was placed in a m...

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Main Authors: Luca Banchelli, Georgi Todorov, Vladimir Stavrov, Borislav Ganev, Todor Todorov
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Micro
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Online Access:https://www.mdpi.com/2673-8023/4/4/35
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author Luca Banchelli
Georgi Todorov
Vladimir Stavrov
Borislav Ganev
Todor Todorov
author_facet Luca Banchelli
Georgi Todorov
Vladimir Stavrov
Borislav Ganev
Todor Todorov
author_sort Luca Banchelli
collection DOAJ
description In this paper, the impact of Lorentz forces and temperature on the natural frequencies of a piezoresistive sensor composed of two microcantilevers with integrated U-shaped thin-film aluminum heaters are investigated. Two types of experiments were performed. In the first, the sensor was placed in a magnetic field so that the current flowing in the heater, in addition to raising the temperature, produced Lorentz forces, inducing normal stresses in the plane of one of the microcantilevers. In the second, which were conducted without magnetic fields, only the temperature variation of the natural frequency was left. In processing of the results, the thermal variations were subtracted from the variations due to both Lorentz forces and temperature in the natural frequency, resulting in the influence of the Lorentz forces only. Theoretical relations for the Lorentz frequency offsets were derived. An indirect method of estimating the natural frequency of one of the cantilevers, through a particular cusp point in the amplitude–frequency response of the sensor, was used in the investigations. The findings show that for thin microcantilevers with silicon masses on the order of 4 × 10<sup>−7</sup> g and currents of 25 µA, thermal eigenfrequency variations are dominant. The results may have applications in the design of similar microsensors with vibrational action.
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spelling doaj-art-c9de16d89b18490d94de3032e533da322025-08-20T02:56:59ZengMDPI AGMicro2673-80232024-10-014457258410.3390/micro4040035Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass DetectionLuca Banchelli0Georgi Todorov1Vladimir Stavrov2Borislav Ganev3Todor Todorov4Department of Theory of Mechanisms and Machines, Faculty of Industrial Technology, Technical University of Sofia, 1797 Sofia, BulgariaDepartment of Manufacturing Technology and Systems, Faculty of Industrial Technology, Technical University of Sofia, 1797 Sofia, BulgariaAMG Technology Ltd., Microelectronica Industrial Zone, 2140 Botevgrad, BulgariaDepartment of Electronics, Faculty of Electronic Engineering and Technologies, Technical University of Sofia, 1797 Sofia, BulgariaDepartment of Theory of Mechanisms and Machines, Faculty of Industrial Technology, Technical University of Sofia, 1797 Sofia, BulgariaIn this paper, the impact of Lorentz forces and temperature on the natural frequencies of a piezoresistive sensor composed of two microcantilevers with integrated U-shaped thin-film aluminum heaters are investigated. Two types of experiments were performed. In the first, the sensor was placed in a magnetic field so that the current flowing in the heater, in addition to raising the temperature, produced Lorentz forces, inducing normal stresses in the plane of one of the microcantilevers. In the second, which were conducted without magnetic fields, only the temperature variation of the natural frequency was left. In processing of the results, the thermal variations were subtracted from the variations due to both Lorentz forces and temperature in the natural frequency, resulting in the influence of the Lorentz forces only. Theoretical relations for the Lorentz frequency offsets were derived. An indirect method of estimating the natural frequency of one of the cantilevers, through a particular cusp point in the amplitude–frequency response of the sensor, was used in the investigations. The findings show that for thin microcantilevers with silicon masses on the order of 4 × 10<sup>−7</sup> g and currents of 25 µA, thermal eigenfrequency variations are dominant. The results may have applications in the design of similar microsensors with vibrational action.https://www.mdpi.com/2673-8023/4/4/35Lorentz forcetemperature frequency coefficient (TCF)dual-microcantilever sensornatural frequencyvibrations
spellingShingle Luca Banchelli
Georgi Todorov
Vladimir Stavrov
Borislav Ganev
Todor Todorov
Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
Micro
Lorentz force
temperature frequency coefficient (TCF)
dual-microcantilever sensor
natural frequency
vibrations
title Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
title_full Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
title_fullStr Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
title_full_unstemmed Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
title_short Evaluation of the Influence of Lorentz Forces on the Natural Frequencies of a Dual-Microcantilever Sensor for Ultralow Mass Detection
title_sort evaluation of the influence of lorentz forces on the natural frequencies of a dual microcantilever sensor for ultralow mass detection
topic Lorentz force
temperature frequency coefficient (TCF)
dual-microcantilever sensor
natural frequency
vibrations
url https://www.mdpi.com/2673-8023/4/4/35
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