• Journal of Magnetics
• /
• v.7 no.1
• /
• pp.21-23
• /
• 2002

The magnetoimpedance of $Fe_{91.5-x}Zr_7B_xCu_1Al_{0.5}$alloys has been measured to investigate the influence of structural changes in the nanocrystallization process after thermal treatment. Annealing was performed at temperatures of $350^\circ{C}$, $450^\circ{C}$, and $550^\circ{C}$ for 1 hour in a vacuum. Ultra soft magnetic behavior was observed in the samples annealed at $550^\circ{C}$. The magnetoimpedance ratio and the longitudinal permeability ratio coincided with the softness of the magnetic properties of the thermally treated samples.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2004.06a
• /
• pp.196-197
• /
• 2004

• Journal of Magnetics
• /
• v.15 no.4
• /
• pp.194-198
• /
• 2010

In our present work, we developed a GMI (giant magnetoimpedance) sensor system to detect magnetic fields in the milli gauss range based on the asymmetric magnetoimpedance (AGMI) effect in Co-based amorphous ribbon with self bias field produced by field-annealing in open air. The system comprises magnetoimpedance sensor probe, signal conditioning circuits, A/D converter, USB controller, notebook computer, and program for measurement and display. Sensor probe was constructed by wire-bonding the cobalt based amorphous ribbon with dimensions $10\;mm\;{\times}\;1\;mm\;{\times}\;20\;{\mu}m$ on a printed circuit board. Negative feedback was used to remove the hysteresis and temperature dependence and to increase the linearity of the system. Sensitivity of the milli gauss meter was 0.3 V/Oe and the magnetic field resolution and environmental noise level were less than 0.01 Oe and 2 mOe, respectively, in an unshielded room.

• Journal of the Korean Magnetics Society
• /
• v.7 no.1
• /
• pp.1-6
• /
• 1997

The frequency dependence of magnetoimpedance (MI) effect in amorphous $Fe_{78}B_{13}Si_9$ alloy has been obtained. Magnetoimpedance (MI) effect is a high-frequency phenomenon, which describes the changes of impedance in any ferromagnetic sample, when a magnetic field is applied on it. MIR (Magnetoimpedance ratios) is defined as $\Delta$ Z/Z ≡ [Z (0) / Z ($H_s$)]-1 where $H_s$ is the saturating field along the long side of the sample, The MIR of the samples annealed in vacuum has been decreased normally except that the sample annealed at 5 MHz has been reached as much as 58%.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.208-209
• /
• 2002

Recently an asymmetric giant magnetoimpedance (GMI) profile has been observed in Co-based amorphous ribbons annealed at the weak field [1-4]. This phenomenon has attracted a large interest due to its practical application to sensitive magnetic sensors. It is known [5.6] that in magnetic materials, the magnetoimpedance is caused by the effect of the magnetic field on the transverse magnetic permeability of a near-surface layer. In consequence of it, the value of the magnetoimpedance depends strongly on near-surface magnetic properties of the sample. (omitted)

• Proceedings of the Korean Magnestics Society Conference
• /
• 2003.06a
• /
• pp.88-89
• /
• 2003

During the past decade, giant magnetotransport phenomena such as giant magetoresistance (GMR) in thin films and in manganese perovskites, and, giant magnetoimpedance (GMI) in soft magnetic amorphous ribbons, have brought much interest in the basic physical understanding and their applications as magnetic recording heads and in magnetic sensors technology. Among the parameters required for the quality of a magnetic sensor, temperature dependences of GMR and GMI profiles are playing an important role. In the present work, we have studied temperature dependences of the longitudinal permeability and giant magnetoimpedance effect in $Co_{70}$F $e_{5}$S $i_{15}$ N $b_{2.2}$C $u_{0.8}$ $B_{7}$ amorphous ribbons expecting as a promising candidate in the domain of magnetic sensors.rs.rs.rs.s.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2011.12a
• /
• pp.129-130
• /
• 2011

• Proceedings of the Korean Magnestics Society Conference
• /
• 2000.09a
• /
• pp.502-503
• /
• 2000

• Proceedings of the Korean Magnestics Society Conference
• /
• 2008.12a
• /
• pp.283.2-283.2
• /
• 2008

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.337-340
• /
• 2004

To develop the highly sensitive Magneto-Impedance sensor, the amorphous ribbon was micro-processed to meander type sensor pattern and the filter circuit was constructed with this pattern. Its external magnetic field dependence of impedance and the output properties of the filter circuit were investigated. The impedance of the pattern had a peak value at the magnetic field of 10 Oe and its changing ratio was about 280%. The impedance change per unit magnetic field was about 36%, in which the output with high sensitivity and linearity could be obtained. The output sensitivity was about 7%/Oe at bias field of 6 Oe..