• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.36.2-36.2
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• 2008

• Journal of Magnetics
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• v.11 no.4
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• pp.195-207
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• 2006

The recently published and new results on design and fabrication of magnetophotonic crystals of different dimensionality are surveyed. Coupling of polarized light to 3D photonic crystals based on synthetic opals was studied in the case of low dielectric contrast. Transmissivity of opals was demonstrated to strongly depend on the propagation direction of light and its polarization. It was shown that in a vicinity of the frequency of a single Bragg resonance in a 3D photonic crystal the incident linearly polarized light excites inside the crystal the TE- and TM-eigen modes which passing through the crystal is influenced by Brags diffraction of electromagnetic field from different (hkl) sets of crystallographic planes. We also measured the faraday effect of opals immersed in a magneto-optically active liquid. It was shown that the behavior of the faraday rotation spectrum of the system of the opal sample and magneto-optically active liquid directly interrelates with transmittance anisotropy of the opal sample. The photonic band structure, transmittance and Faraday rotation of the light in three-dimensional magnetophotonic crystals of simple cubic and face centered cubic lattices formed from magneto-optically active spheres where studied by the layer Korringa-Kohn-Rostoker method. We found that a photonic band structure is most significantly altered by the magneto-optical activity of spheres for the high-symmetry directions where the degeneracies between TE and TM polarized modes for the corresponding non-magnetic photonic crystals exist. The significant enhancement of the Faraday rotation appears for these directions in the proximity of the band edges, because of the slowing down of the light. New approaches for one-dimensional magnetophotonic crystals fabrication optimized for the magneto-optical Faraday effect enhancement are proposed and realized. One-dimensional magnetophotonic crystals utilizing the second and the third photonic band gaps optimized for the Faraday effect enhancement have been successfully fabricated. Additionally, magnetophotonic crystals consist of a stack of ferrimagnetic Bi-substituted yttrium-iron garnet layers alternated with dielectric silicon oxide layers of the same optical thickness. High refractive index difference provides the strong spatial localization of the electromagnetic field with the wavelength corresponding to the long-wavelength edge of the photonic band gap.

• Journal of Magnetics
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• v.8 no.1
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• pp.50-59
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• 2003

Spatial light modulators (SLMs) are centrally important devices in volumetric recording, data Processing, Pattern recognition and other optical systems. Various types of reusable SLMs with two-dimensional pixel arrays have been intensively developed. Of these, magneto-optic spatial light modulators (MOSLMs) have advantages of high switching speed, robustness, nonvolatility, and radioactive resistance. In this article, we review recent development work on MOSLMs, mainly in relation to our own studies.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.511-519
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• 1994

The effect of the deposition conditions, such as the base pressure, working pressure, sputtering power, pre-sputtering, and deposition thickness in facing targets sputtering system(FTS), on the oxidation of the TbFeCo thin films was studied by investigating the magneto-optical properties as well as oxygen analysis by the AES depth profiles. The results showed that the base pressure did not affect the magnetic properties so much, probably due to the short flight distance of the sputtered particles. At the higher sputtering power and lower working pressure with pre-sputtering the oxidation of TbFeCo thin films was decreased. As the film thickness increased the TbFeCo thin films showed the perpendicular anisotropy from in-plane anisotropy overcoming the oxidation effect at the beginning of the sputtering.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.640-648
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• 2004

This paper describes a new magnetization method for non-destructive testing with magneto-optical sensor (denoted as MO sensor) which have the following characteristic : high observation sensitivity, independence of the crack orientation, and precise imaging of a complex crack geometry such as multiple cracks. When a magnetic field is applied normally to the surface of a specimen which is significantly larger than its defects, approximately the same magnetic charge per unit area occurs on the surface of the specimen. If there is a crack in the specimen, magnetic charge per unit area has the same value at the bottom of the crack. The distribution of the vertical component of the magnetic flux density, B$\_$Z/, is almost uniform over the no-crack area (denoted as B$\_$Z,BASE/), while the magnetic flux density is smaller in the surroundings of the crack(denoted as B$\_$Z,CRACK/) If B$\_$Z, BASE/ is a bit larger than the saturated magnetic flux density of the MO sensor (B$\_$s/) , then small magnetic domains occur over the crack area and a large domain over the non-crack area because B$\_$Z,CRACK/ is smaller than B$\_$s/.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.7-12
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• 2005

We have observed the nonlinear magneto-optic effect(NMOE) based on atomic coherence in $^{87}$ Rb D$_1$-line using the Rb vapor cell containing 50 Torr of Ne. The width of the NMOE signal was measured to be 2$\pi$${\times}$464 Hz, when the peak-to-peak B-field variation was 1 mGauss. The result of this work may be applied to a high-sensitivity magnetometer.

• Journal of Magnetics
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• v.8 no.4
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• pp.133-137
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• 2003

The magnetostatic properties of the as-deposited and annealed at T=300 and 400$^{\circ}C$ Ni films were investigated employing both magneto-optical magnetometer and VSM. The Ni films of 50∼200 nm thicknesses were prepared by DC magnetron sputtering technique. The strong influence of annealing temperature on magnetostatic properties of the studied samples was discovered. For the annealed Ni films, the increase of the coercivity H$_c$ (up to 4 times) in comparison with that of as-deposited samples was revealed. The obtained results were explained by using crystallographic structural data of the samples.

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.1-13
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• 2014

Semiconductor quantum structures are often characterized by their energy gaps which are modified by the quantum size effect. Energy levels in semiconductors can be realized by optical transitions within confined structures. Photoluminescence spectroscopy in magnetic fields at low temperatures has proved to be a powerful technique for investigating the electronic states of quantum semiconductor heterostructures and offers a complimentary tool to electrical transport studies. In this review, we examine comprehensive investigations of magneto-excitonic and Landau transitions in a large variety of undoped and doped quantum-well structures. Strong magnetic fields change the diamagnetic energy shift of free excitons from quadratic to linear in B in undoped single quantum well samples. Two-dimensional electron gas induced by modulation doping shows pronounce quantum oscillations in integer quantum Hall regime and discontinuous transition at ${\nu}=1$. Such discontinuous transition can be explained as the formation of spin waves or Skyrmions.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.1-6
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• 2006

We investigated the characteristics of the nonlinear magneto-optic effect (NMOE) depend on the transitions, the laser intensity and the temperature of the vapor cell, in the $D_1$ transition of $^{87}Rb$ atoms by using the Rb vapor cell contained with buffer gas of Ne 6.7 kPa. The size and the width of NMOE signal were increased according to the light intensity and temperature in the transition of F=2$\to$F'=2. However, In the case of using the F=2$\to$F'=1 transition, the size of the signal could be increased according to the light intensity without additional broadening of the width. We confirmed that the sensitivity of detecting small magnetic flux improved in this transition, and explained these effects by the different of the CPT configuration between Zeeman sublevels. At the optimal condition in experiment, the sensitivity of this system was evaluated less then $70pT/\sqrt{Hz}$.

• Journal of the Korean Magnetics Society
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• v.25 no.1
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• pp.1-3
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• 2015

We demonstrate here an optical measurement technique to quantify the spin-orbit torques. The magnetization dynamics induced by the spin-orbit torques with a sinusoidal current injection is measured by use of polar magneto-optical Kerr effect. The measured signal is then analyzed based on the Landau-Lifhshitz-Gilbert equation with consideration of the spin-orbit torques. The present measurement technique is applied to Pd/Co/Pt films and then, the longitudinal and transverse components of the spin-orbit torques are successfully quantified. The present optical technique provides an alternative way to quantify the spin-orbit torques.