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The authors wish to make the following corrections to the original paper [...].
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The core of a Gigahertz Spin Rotation (GSR) sensor, a compact and highly sensitive magnetic sensor, is composed of Co-Fe-based amorphous magnetic wire with a diameter of 10 µm. Observations of the magnetic domain structure showed that this magnetic wire has unusual magnetic noise characteristics. Bamboo-shaped magnetic domains a few hundred micrometers in width were observed to form inside the wire, and smaller domains a few micrometers across were observed to form inside these larger domains. The magnetic domain pattern changed abruptly when an external magnetic field was applied to the wire. Herein is shown how these changes may be a source of magnetic noise in the wire.
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In this report, we studied the dependence of output voltage on the damping constant, the frequency of the pulse current, and the wire length of zero-magnetostriction CoFeBSi wires using multiphysics simulation considering eddy currents in micromagnetic simulations. The magnetization reversal mechanism in the wires was also investigated. As a result, we found that a high output voltage can be achieved with a damping constant of ≥0.03. We also found that the output voltage increases up to a pulse current of 3 GHz. The longer the wire length, the lower the external magnetic field at which the output voltage peaks. This is because the demagnetization field from the axial ends of the wire is weaker as the wire length is longer.
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The GigaHertz spin rotation (GSR) effect was observed through the excitement of Giga Hertz (GHz) pulse current flowing through amorphous wire. The GSR sensor that was developed provides excellent features that enhanced magnetic sensitivity and sine functional relationship, as well as good linearity, absence of hysteresis, and low noise. Considering the GHz frequency range used for the GSR sensor, we assume that the physical phenomena associated with the operation of the sensor are based on spin reduction and rotation of the magnetization. The proper production technology needed was developed and a micro-sized GSR sensor was produced by directly forming micro coils on the surface of the application-specific integrated circuit (ASIC). Some prototypes of the ASIC type GSR sensor have been produced in consideration of applications such as automotive use, mobile device use, and medical use. Therefore, we can conclude that GSR sensors have great potential to become promising magnetic sensors for many applications.
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We indicate that the Magneto-Impedance sensor using amorphous wires has reached a new stage to view "Super MI sensor technology" based on three main advantageous factors of (i) micro sized head and micro power consumption chip, (ii) ultra-high sensitivity micro magnetic sensor with 1 pico-Tesla resolution at the room temperature without any electromagnetic shielding, and (iii) ultra-quick response magnetic sensor with GHz operation. We summarize systematically the magneto-impedance technology with the basic principle and mechanisms of three advantageous features for constitution of various high performance new sensor devices such as the electronic compass chip for mobile phones and smart phones and portable sensors for the magneto-encephalography, the magneto-spinography, and various bio-cell magnetic measurements. Possibility of new application to MI antenna in magnetic telecommunications is also discussed.
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PURPOSE: The purpose of this study was to develop a new device to measure continuously the vertical dimension of the human jaw relation using magnetic sensors. METHODS: A sensor unit was made of six MI (Magneto-Impedance) sensors (AMI302 4.0 x 3.5 x 1.4 mm, Aichi Steel Corp.) placed in a line at intervals of 4 mm. The unit was positioned to the head by a glasses-type sensor holder. A target magnet (3 mm in diameter, 12 mm in length) was set in a resin board positioned on the mentum with adhesive tape. 1) In vitro experiments using a precision-movement stage were conducted. 2) One healthy volunteer (age: 25 years) was instructed to perform a jaw opening-closing task with 10 mm range of motion. Before and after the task his jaw position in the intercuspal position was measured for five minutes. The jaw movements were recorded simultaneously using a 6-degree-of-freedom jaw-tracking device. RESULTS: The mean square error of the in vitro experiment was 0.06 mm under the worst conditions. The mean square error of the positional accuracy was 0.35 mm. The reproducibility of the intercuspal position was 0.33 mm. These values correspond to about 16% of the value of the shift phenomenon of the resting position (approximately 2.2 mm). CONCLUSION: Our new device using an MI sensor enables the vertical dimension to be recorded continuously with sufficient accuracy.