scholarly journals Nondestructive Detection of Magnetic Contaminant in Aluminum Casting Using Thin Film Magnetic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4063
Author(s):  
Tomoo Nakai
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Single Layer ◽  
Static Field ◽  
Inspection System ◽  
Aluminum Casting ◽  
Logarithmic Amplifier ◽  
Impedance Sensor ◽  
Driving Circuit ◽  
Normal Magnetic Field

The thin film magneto-impedance sensor is useful for detecting a magnetic material nondestructively. The sensor made by single layer uniaxial amorphous thin film has a tolerance against surface normal magnetic field because of its demagnetizing force in the thickness direction. Our previous study proposed the sensitive driving circuit using 400 MHz high frequency current running through the sensor to detect the logarithmic amplifier. We also confirmed the sensitivity of the sensor within 0.3 T static normal magnetic field, which resulted in detection of 5 × 10−8 T of 5 Hz signal. This paper proposes a nondestructive inspection system for how detecting a contaminant of small tool steel chipping in aluminum casting specimen would be carried out. Three channel array sensors installed in the 30 mT static field detecting area were fabricated and experimentally showed a detection of low remanence magnetic contaminant in a bulk aluminum casing specimen.

scholarly journals Magneto-Impedance Sensor Driven by 400 MHz Logarithmic Amplifier

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 355 ◽  
Author(s):  
Tomoo Nakai
Keyword(s):  
Thin Film ◽  
High Frequency ◽  
High Sensitivity ◽  
Smart Manufacturing ◽  
Voltage Controlled Oscillator ◽  
High Frequency Signal ◽  
Logarithmic Amplifier ◽  
Impedance Variation ◽  
Voltage Signal ◽  
Impedance Sensor

A thin-film magnetic field sensor is useful for detecting foreign matters and nanoparticles included in industrial and medical products. It can detect a small piece of tool steel chipping or breakage inside the products nondestructively. An inspection of all items in the manufacturing process is desirable for the smart manufacturing system. This report provides an impressive candidate for realizing this target. A thin-film magneto-impedance sensor has an extremely high sensitivity, especially, it is driven by alternatiing current (AC) around 500 MHz. For driving the sensor in such high frequency, a special circuit is needed for detecting an impedance variation of the sensor. In this paper, a logarithmic amplifier for detecting a signal level of 400 MHz output of the sensor is proposed. The logarithmic amplifier is almost 5 mm × 5 mm size small IC-chip which is widely used in wireless devices such as cell phones for detecting high-frequency signal level. The merit of the amplifier is that it can translate hundreds of MHz signal to a direct current (DC) voltage signal which is proportional to the radio frequency (RF)signal by only one IC-chip, so that the combination of a chip Voltage Controlled Oscillator (VCO), a magneto-impedance (MI) sensor and the logarithmic amplifier can compose a simple sensor driving circuit.

Impedance Change Ratio and Sensitivity of Micromachined Single-Layer Thin Film Magneto-Impedance Sensor

2019 ◽  
Vol 10 ◽  
pp. 1-5 ◽  
Author(s):  
Hiroaki Kikuchi ◽  
Taisei Umezaki ◽  
Takuya Shima ◽  
Chihiro Sumida ◽  
Suguru Oe
Keyword(s):  
Thin Film ◽  
Single Layer ◽  
Impedance Change ◽  
Layer Thin Film ◽  
Impedance Sensor

Wavelength-tunable superresolution imaging with a ferrite superlens

2016 ◽  
Vol 30 (34) ◽  
pp. 1650408
Author(s):  
Xiaohua Wang ◽  
Youwen Liu ◽  
Yuncai Feng ◽  
Daxing Dong
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Numerical Simulation ◽  
Single Layer ◽  
Film Material ◽  
Thin Film Material ◽  
Superresolution Imaging ◽  
Wavelength Tunable ◽  
Ferrite Material ◽  
Simulation Results

We theoretically propose a system capable of wavelength-tunable sub-diffraction-limited imaging by a single planar magnetic superlens, which is made of [Formula: see text]-negative ferrite material (MNM) slab. Our theoretical and numerical simulation results demonstrate that the working wavelength of this planar superlens can be well tuned with the external magnetic field since the permeability of ferrite material LuBiIG is adjusted by the applied magnetic field. The resolution of the magnetic superlens with 300 [Formula: see text]m thickness LuBiIG film is smaller than [Formula: see text]/20, and the resolution is higher with thinner film. It may provide a potential way to design a wavelength-tunable magnetic superlens with the single layer of ferrite thin film material.

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