rus
Issue #7-8/2018
V.Amelichev, S.Generalov, S.Nikiforov, D.Gorelov, D.Grigoriev
The investigation of membrane element with thin-film nanostructured magnetostrictive layer in variable magnetic field
The investigation of membrane element with thin-film nanostructured magnetostrictive layer in variable magnetic field
The results of investigations of figurine-shaped membrane element with thin-film nanostructured magnetostrictive layer in variable magnetic field have been presented. The perspective of manufacturing microsystems for conversion of magnetic field into the mechanical displacement of a thin membrane has been discussed.
Теги: elastomer flexible printing compositions stretchable electronics гибкие печатные составы растягиваемая электроника эластометр
Development of perspective MEMS, as a rule, is connected with a number of investigations devoted to a possibility to combine technological processes in a new technology which allows of constructing new devices and units for microsystem equipment. Thin membrane elements are widely used in the design of pressure transducers, most often with a tensor-resistive effect. Evolution of this technology has led to a possibility of creating thinner membranes and acoustic pressure transducers based on them. The most common principles of operation for conversion of acoustic pressure using thin membranes are the changes in capacitance, generation of EMF or charge, modulation of the electromagnetic signal or medium conductivity. The technologies of thin membrane manufacturing are developed individually according to one or another principle of acoustic pressure transducer operation. As a rule, engineers have been focused on existing technologies and technological processes during the new devices development based on thin membrane elements. It is imperative to take into account a level of mechanical stresses in thin membrane element structures when choosing technological processes and their compatibility and applicability [1]. Usually, high levels of mechanical compressive stresses in a membrane structure do not cause visually observed deformations but induce its low compliance to an external influence. Besides, unclenching mechanical stresses in a membrane structure lead to visual deformations ("booklet-shaped deformations") and make a reason of low compliance to external influence. In order to improve the structural characteristics and ability of membrane’s material to resist the forming of deformation the ridged sections are introduced into their design. The ridged sections are necessary to unload the central section of the membrane from additional mechanical stresses and, hence, increase its compliance not only to external influence but to impact of element placed in a central part of membrane. As elements capable of exerting mechanical effects on a thin membrane, it is necessary to consider those that have a dependence of linear dimension on the external field, since electrical contact, in this case, is excluded, due to the presence of a ridged ring section of the membrane. The elements formed using magnetostrictive thin film nanostructures have a property to change their geometrical dimensions in a magnetic field. The list of magnetostrictive materials is so wide and the technology of forming elements on its base, in some cases, requires adding of new technological processes using special equipment and understanding of applicability for integrated circuit and chips manufacturing. [2]. One of the most well-proven technologies for manufacturing of elements with magnetostrictive effects are spray technological processes of thin-film magnetoresistive nanostructures (TMRNS). Control of magnetic parameters in this technology is the one of the most important technological operations after spraying of TMRNS. Control equipment used for this operation allows to measure not only all magnetic parameters but to determine the magnetostrictive value in the plates composition. It is well known that magnetostrictive effect is a negative phenomenon for TMRNS used for magnetoresistive microsystems and its value is necessary to decrease by choosing of alloy composition to be sprayed. It is possible to use existed targets made of allow based on Fe, Ni and Co applying the new technology that is combining the forming of thin membranes and thin-film TMRNS elements at the first stage. For experimental technological engineering, an alloy of the above-mentioned metals with a 20 % Co content was chosen. This alloy has a magnetostrictive effect nearby of 3–4 ppm and may be replaced by more effective one in a future. It was shown in a Fig.1 the photo of a crystal with thin dialectical membrane equipped with round thin-film element based on TMRNS in a central part. As we can see, the central area placed inside of the ring ridges has visible deformations around of circular TMRNS element. It means that mechanical stresses are increased in this membrane’s area because of formed element. Obviously, it is essential to perform an experimental work on optimization of composition and nanostructured magnetostrictive layer thickness in new merged technology in order to minimize mechanical stresses in a central part of the membrane.
The vertical displacement of circular element based on TMRNS using MSA-500 microchip analyzer by optical method based on Doppler effect have been investigated. Firstly, we determined the natural frequency of a membrane under the 0,2 Pa acoustic pressure influence in the region of 0 Hz up to 5 kHz. Fig.2 presents a MSA-500 display screenshot of the ARF of the membrane under the acoustic influence of variable frequency. It was shown that the membrane natural frequency equals 3.5 kHz at 43 nm amplitude.
All further investigations of an influence of TMRNS element magnetostrictive properties on the membrane’s displacement were carried out under the variable magnetic field only. The MSA-500 analyzer was equipped with special attachment which is to provide variable magnetic fields in a central part of the membrane with intensity of 54 Oe and frequency of up to 10 kHz. To control the magnetic field in the location of the membrane the milliteslameter TP2-2U was used. The general view of MSA-500 analyzer with special attachment to control the magnetic field in the membrane’s area is presented in the Fig.3. Given the anisotropic properties of TMRNS, the membrane in the attachment was positioned so that the alternating magnetic field was orthogonal to the easy axis of magnetization. It was found that maximal amplitude of the membrane is observed at the values of magnetic field in a region of 0,9–1,2 mT (see Fig.4) at magnetic field frequencies of 500 Hz, 1,000 Hz and 2,000 Hz. Besides, it was shown that an amplitude of the membrane reaches 204 nm under the influence of magnetic field of 1 mT at frequency of 3,5 kHz (natural frequency of the membrane).
Thus, the research has shown that on the basis of the new combined technology it can be possible to develop the microsystems, where thin-film magnetostrictive nanostructure formed on thin ridged membrane or other element with corresponding properties can be used as an element of a microdrive. In order to obtain the high effectiveness of magnetostrictive materials applications on the surfaces of elastic elements the additional experimental researches focused on optimal balance of their thickness are strongly required.
The research was accomplished with financial support of The Ministry of Education and Science of the Russian Federation in the frame of project No. 8.8624.2017 for 2018 year.
Investigation of the developed membrane parameters was carried out with the aid of the instrumentation of SRF "Functional control and diagnostics of micro and nanosystem technique" (Shared Core Facilities) on a base of SDC "Technological Center" (Scientific Technological Center) [3]. ■
The vertical displacement of circular element based on TMRNS using MSA-500 microchip analyzer by optical method based on Doppler effect have been investigated. Firstly, we determined the natural frequency of a membrane under the 0,2 Pa acoustic pressure influence in the region of 0 Hz up to 5 kHz. Fig.2 presents a MSA-500 display screenshot of the ARF of the membrane under the acoustic influence of variable frequency. It was shown that the membrane natural frequency equals 3.5 kHz at 43 nm amplitude.
All further investigations of an influence of TMRNS element magnetostrictive properties on the membrane’s displacement were carried out under the variable magnetic field only. The MSA-500 analyzer was equipped with special attachment which is to provide variable magnetic fields in a central part of the membrane with intensity of 54 Oe and frequency of up to 10 kHz. To control the magnetic field in the location of the membrane the milliteslameter TP2-2U was used. The general view of MSA-500 analyzer with special attachment to control the magnetic field in the membrane’s area is presented in the Fig.3. Given the anisotropic properties of TMRNS, the membrane in the attachment was positioned so that the alternating magnetic field was orthogonal to the easy axis of magnetization. It was found that maximal amplitude of the membrane is observed at the values of magnetic field in a region of 0,9–1,2 mT (see Fig.4) at magnetic field frequencies of 500 Hz, 1,000 Hz and 2,000 Hz. Besides, it was shown that an amplitude of the membrane reaches 204 nm under the influence of magnetic field of 1 mT at frequency of 3,5 kHz (natural frequency of the membrane).
Thus, the research has shown that on the basis of the new combined technology it can be possible to develop the microsystems, where thin-film magnetostrictive nanostructure formed on thin ridged membrane or other element with corresponding properties can be used as an element of a microdrive. In order to obtain the high effectiveness of magnetostrictive materials applications on the surfaces of elastic elements the additional experimental researches focused on optimal balance of their thickness are strongly required.
The research was accomplished with financial support of The Ministry of Education and Science of the Russian Federation in the frame of project No. 8.8624.2017 for 2018 year.
Investigation of the developed membrane parameters was carried out with the aid of the instrumentation of SRF "Functional control and diagnostics of micro and nanosystem technique" (Shared Core Facilities) on a base of SDC "Technological Center" (Scientific Technological Center) [3]. ■
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