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Lee, Dong-Ryeol
- Journal of the Korean Magnetics Society
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- v.20 no.4
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- pp.160-166
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- 2010
X-ray resonant magnetic scattering (XRMS) allows us to extract magnetic depth profiles in magnetic multilayers and magnetization distribution in magnetic nanostructures in element-specific manner using x-ray reflectivity and diffraction. XRMS is explained with a brief introduction and examples of magnetic structures and magnetic switching mechanism in magnetic multilayers and nanostructures.
https://doi.org/10.4283/JKMS.2010.20.4.160 인용 PDF KSCI

Song, Kyung Mee;Kim, Dong-Ok;Kim, Jae-Sung;Lee, Dong Ryeol;Choi, Jun Woo
- Current Applied Physics
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- v.18 no.11
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- pp.1212-1217
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- 2018
The electric field-induced modifications of magnetic anisotropy in CoFeB/MgO systems are studied using X-ray resonant magnetic scattering and magneto-optical Kerr effect. Voltage dependent changes of the magnetic anisotropy of -12.7 fJ/Vm and -8.32 fJ/Vm are observed for Ta/CoFeB/MgO and Hf/CoFeB/MgO systems, respectively. This implies that the interfacial perpendicular magnetic anisotropy is reduced (enhanced) when electron density is increased (decreased). X-ray resonant magnetic scattering measurements reveal that the small in-plane magnetic component of the remanent state of CoFeB/MgO systems with weak magnetic anisotropy changes depending on the applied voltage leading to modification of the magnetic anisotropy at the CoFeB/MgO interface.
https://doi.org/10.1016/j.cap.2018.05.003 인용 KSCI

Oh, Ju Hyun;Kim, Jung Ho;Jeong, Jung Hyun;Chang, Seo Hyoung
- Current Applied Physics
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- v.18 no.11
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- pp.1225-1229
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- 2018
In this paper, we investigated the electronic structures and defect states of $SrLaMgTaO_6$ (SLMTO) double perovskite structures by using resonant inelastic x-ray scattering. Recently, $Eu^{3+}$ doped SLMTO red phosphors have been vigorously investigated due to their higher red emission efficiency compared to commercial white light emitting diodes (W-LED). However, a comprehensive understanding on the electronic structures and defect states of host SLMTO compounds, which are specifically related to the W-LED and photoluminescence (PL), is far from complete. Here, we found that the PL spectra of SLMTO powder compounds sintered at a higher temperature, $1400^{\circ}C$, were weaker in the blue emission regions (at around 400 nm) and became enhanced in near infrared (NIR) regions compared to those sintered at $1200^{\circ}C$. To elucidate the difference of the PL spectra, we performed resonant inelastic x-ray spectroscopy (RIXS) at Ta L-edge. Our RIXS result implies that the microscopic origin of different PL spectra is not relevant to the Ta-related defects and oxygen vacancies.
https://doi.org/10.1016/j.cap.2018.05.014 인용 KSCI

Huang, H.;Jang, H.;Kang, B.Y.;Cho, B.K.;Kao, C.C.;Liu, Y.J.;Lee, J.S.
- Current Applied Physics
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- v.18 no.11
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- pp.1205-1211
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- 2018
The frustrated magnet has been regarded as a system that could be a promising host material for the quantum spin liquid (QSL). However, it is difficult to determine the spin configuration and the corresponding mechanism in this system, because of its geometrical frustration (i.e., crystal structure and symmetry). Herein, we systematically investigate one of the geometrically frustrated magnets, the $TbB_4$ compound. Using resonant soft x-ray scattering (RSXS), we explored its spin configuration, as well as Tb's quadrupole. Comprehensive evaluations of the temperature and photon energy/polarization dependences of the RSXS signals reveal the mechanism of spin reorientation upon cooling down, which is the sophisticated interplay between the Tb spin and the crystal symmetry rather than its orbit (quadrupole). Our results and their implications would further shed a light on the search for possible realization of QSL.
https://doi.org/10.1016/j.cap.2018.05.005 인용 KSCI