Magnetoelastic sensors in combination with nanometer-scale honeycombed thin film ceramic TiO2 for remote query measurement of humidity

Abstract

Ribbonlike magnetoelastic sensors can be considered the magnetic analog of an acoustic bell; in response to an externally applied magnetic field impulse the sensors emit magnetic flux with a characteristic resonant frequency. The magnetic flux can be detected external to the test area using a pick-up coil, enabling query remote monitoring of the sensor. The characteristic resonant frequency of a magnetoelastic sensor changes in response to mass loads ͓L. D. Landau and E. M. Lifshitz, Theory of Elasticity, 3rd ed. ͑Pergamon, New York, 1986͒, p. 100͔. Therefore, remote query chemical sensors can be fabricated by combining the magnetoelastic sensors with a mass changing, chemically responsive layer. In this work magnetoelastic sensors are coated with humidity-sensitive thin films of ceramic, nanodimensionally porous TiO 2 to make remote query humidity sensors.

Soft x-ray reflectometry, hard x-ray photoelectron spectroscopy and transmission electron microscopy investigations of the internal structure of TiO2(Ti)/SiO2/Si stacks

“…TiO 2 films are being extensively studied because of their interesting chemical, electrical and optical properties resulting in widespread applications, e.g., in catalysis, photocatalysis, dye-sensitized photovoltaic cells, gas sensors [6][7][8][9] and pharmaceuticals [10][11][12]. Besides, TiO 2 nanofilms are widely used as protective layers for very large-scale integrated (VLSI) circuits and as antireflective (AR) coatings for optical elements and planar waveguides.…”

Wireless Magnetoelastic Resonance Sensors: A Critical Review

“…A magnetoelastic humidity sensor was built by coating a layer of titanium dioxide (TiO 2 ) on a 4 × 1.3 cm Metglas 2826MB ribbon [4]. As the humidity increases, water vapor is absorbed into the TiO 2 layer, increasing the effective mass on the sensor.…”

“…Magnetoelastic sensors have attracted considerable interest within the sensor community as they form an excellent sensor platform that can be used to measure a wide range of environmental parameters including pressure [1][2][3], humidity [3][4][5], temperature [5][6], liquid viscosity and density [7][8][9][10], thin-film elasticity [11], and chemicals such as carbon dioxide [12][13], ammonia [14], and pH [15]. Magnetoelastic sensors are typically made of amorphous ferromagnetic ribbons or wires, mostly iron-rich alloys such as Fe 40 Ni 38 Mo 4 B 18 (Metglas brand 2826MB) and Fe 81 B 13.5 Si 3.5 C 2 (Metglas 2605SC) ribbons [15] that have a high mechanical tensile strength (~1000-1700 MPa), and a low material cost allowing them to be used on a disposable basis.…”

Ethylene Detection Using Nanoporous PtTiO2 Coatings Applied to Magnetoelastic Thick Films

“…Therefore in-situ ethylene sensors of high-sensitivity are of great interest. As described herein we use nanoporous PtTiO 2 films, the mass/elasticity of which respond to ethylene concentrations, with magnetoelastic sensors [9][10][11][12][13][14][15][16] to measure ethylene at low concentrations (< 1 ppm).…”