• Journal of the Korean Magnetics Society
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• v.26 no.4
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• pp.124-128
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• 2016

We have investigated the electronic structures of intermetallic multilayer (ML) films of [$Co(2{\AA})/Pd(x{\AA})$] (x: the thickness of the Pd sublayer; x = $1{\AA}$, $3{\AA}$, $5{\AA}$, $7{\AA}$, $9{\AA}$) by employing soft X-ray absorption spectroscopy (XAS) and soft X-ray magnetic circular dichroism (XMCD). Both Co 2p XAS and XMCD spectra are found to be similar to one another, as well as to those of Co metal, providing evidence for the metallic bonding of Co ions in [Co/Pd] ML films. By analyzing the measured Co 2p XMCD spectra, we have determined the orbital magnetic moments and the spin magnetic moments of Co ions in [$Co(2{\AA})/Pd(x{\AA})$] ML films. Based on this analysis, we have found that the orbital magnetic moments are enhanced greatly when x increases from $1{\AA}$ to $3{\AA}$, and then do not change much for $x{\geq}3{\AA}$. This finding suggests that the interface spin-orbit coupling plays an important role in determining the perpendicular magnetic anisotropy in [Co/Pd] ML films.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.165-165
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.77-78
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2014.11a
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• pp.39-40
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• 2014

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.594-597
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• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of 0.2Pb(Mg1/3Nb2/3)O3-0.38PbZrO3-0.42PbTiO3 followed by lamination and burnout & co-firing processes. The actuators of 10 10 0.62 nm3 in size were formed in a way that 60 200 m thick ceramics were stacked alternatively with 5 m thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of 90o/180o domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.163-168
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• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of $0.2Pb(Mg_{1/3}Nb_{2/3)O_3-0.38PbZrO_3-0,42PbTiO_3$ followed by lamination and burnout & co-firing processes. The actuators of $10\times10\times0.6~2\textrm{mm}^3$ in size were formed in a way that $60 ~ 200\mu\textrm{m}$ thick were stacked alternatively with $5\mu\textrm{m}$ thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of $90^{\circ}$/$180^{\circ}$ domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.561-566
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• 1995

Additional magnetooptical Kerr effect (AMOKE) was observed in several multilayer structures. For Fe/Pd and Co/Cu Multilayers, AMOKE enhanced the Kerr rotation in short wavelength side, while for Fe/Ag and FeSi/Cu multilayer systems the Kerr rotation enhancement appeared in long wavelength side. A number of ferromagnetic/nonmagnetic/ferromagnetic(FM/NM/FM) sandwiches showed that the AMOKE led to oscillations of Kerr rotation and Kerr ellipticity in certain wavelength range with changing NM layer thickness similar to the oscillatory interlayer coupling. The oscillation of effective optical constants related to the MOKE oscillation was observed for the first time. The mechanisms of the AMOKE were discussed.

• Journal of Magnetics
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• v.7 no.4
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• pp.151-155
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• 2002

In situ stress changes at interfaces of ultrathin magnetic films were measured by means of a non-contact optical fiber bundle displacement detector. A bending of the substrate due to stress of a deposited film was detected in cantilever geometry. The highest sensitivity of 134 mV/$\mu$m for the displacement detector was realized with a help of computer simulation. The detector was applied to in situ stress measurements of Co/Pt and Ni/Pd magnetic multilayer films prepared on the glass substrates by dc magnetron sputtering. The detector turned out to have a submonolayer sensitivity that enables to observe coherent-to-incoherent transition in these mismatched multilayers and even detect the stress changes within the monoatomic coverage. This highly sensitive detector paves new way to probe the stress relaxation at an interface in ultrathin films.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.263-267
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• 1992

We have developed new techniques to measure the magnetization and coercivity of a uniaxial magnetic material using a torque magnetometer. The magnetization could be measured from the slope of the linear region in a plot of the torque ${\tau}/H$ versus the applied field H, when the direction of the applied field was normal to the uniaxial orientation. While, the coercivity could be obtained by taking the value of applied field where the torque was zero, when the direction of the applied field was $(180+{\delta})$ degrees from the uniaxial orientation. The techniques were applied to determine the magnetizations and coercivities of several Co /Pd multilayer thin films and the results were confirmed to be similar within a 2 % difference to those obtained by a vibrating sample magnetometer.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.31-38
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• 2003

In the current electronic technology atmosphere, MEMS (Microelectromechanical System) technology is regarded as one of promising device manufacturing technologies to realize market-demanding device properties. In the packaging of MEMS devices, the packaged structure must maintain hermeticity to protect the devices from a hostile atmosphere during their operations. For such MEMS device vacuum packaging, we introduce the LTCC (Low temperature Cofired Ceramic) packaging technology, in which embedded passive components such as resistors, capacitors and inductors can be realized inside the package. The technology has also the advantages of the shortened length of inner and surface traces, reduced signal delay time due to the multilayer structure and cost reduction by more simplified packaging processes owing to the realization of embedded passives which in turn enhances the electrical performance and increases the reliability of the packages. In this paper, the leakage rate of the LTCC package having several interfaces was measured and the possibility of LTCC technology application to MEMS devices vacuum packaging was investigated and it was verified that improved hermetic sealing can be achieved for various model structures having different types of interfaces (leak rate: stacked via; $4.1{\pm}1.11{\times}10^{-12}$/ Torrl/sec, LTCC/AgPd/solder/Cu-tube; $3.4{\pm}0.33{\times}10^{-12}$/ Torrl/sec). In real application of the LTCC technology, the technology can be successfully applied to the vacuum packaging of the Infrared Sensor Array and the images of light-up lamp through the sensor way in LTCC package structure was presented.