• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.196-201
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• 2009

In order to give emission functionality for laponite the laponite-X (x = Eu, Tb) phosphors were prepared by calcination of cryogels which were prepared through Na ion exchange reaction with Eu and Tb ions. Thermal stability and emission properties of new laponite-X (X = Eu, Tb) phosphors were investigated by X-ray diffractormeter and UV/VUV spectrofluorometer. The phosphors were stable around up to $600^{\circ}C$ and new crystalline phases were observed at $700^{\circ}C$. Red and green emissions of phosphors under UV/VUV excitation were also identified at $300^{\circ}C$ and $500^{\circ}C$ as emission peaks of $Eu^{3+}$ and $Tb^{3+}$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.951-954
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• 2004

본 논문에서는 DLC(Diamond-like Carbon) 박막과 기판 사이에 금속층을 포함하는 DLC 박막의 기계적 특성을 분석하였다. 금속층은 sputtering법을 사용하고, DLC 박막은 PECVD법을 사용하여 각각 중착하였다. 티타늄(Ti), 니켄(Ni), 크롬(Cr)을 각 중간 금속층으로 사용한 후 DLC 박막과 실리콘(Si) 기판 간의 기계적 특성을 분석하였다. 각 막의 두께는 FE-SEM으로 확인하였고, DLC 박막의 구조 평가는 Raman spectrometer를 사용하여 분석하였으며, 각 금속층과 DLC 박막의 표면 상태는 AFM을 이용하여 확인하였다. XRD 분석을 통하여 박막의 격자분석을 하였고, SIMS(secondary ion mass spectrometry) 분석을 통하여 DLC 박막의 depth Profile을 확인하였다.

• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.1-5
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• 2003

Magnetic and structural properties of $(CoFe_2O_4)_{1-x}(Y_3Fe_5O_{12})_x$ powders (0 $\leq$ x $\leq$ 1) grown by a conventional ceramic method were investigated using X-ray diffractormeter (XRD), scanning electron microscopy (SEM), Mossbauer spectroscopy and vibrating sample magnetometer (VSM). The XRD results for the powders annealed at 120$0^{\circ}C$ indicated that no other peak was observed except for the ones from cobalt ferrite and the garnet powder. SEM micrographs indicated that cobalt ferrite and garnet powders were aggregated and completely formed together. It was hard to identify which part of the powders was the garnet or the cobalt ferrite. Mossbauer spectra for powders grown separately and mixed mechanically consisted of sub-spectra of cobalt ferrite and garnet, however, powders annealed together had an extra sub-spectrum, which was related with the interaction between iron ions at the grain surfaces of cobalt ferrite and the garnet: cobalt ferrite and garnet particles were located very closely. The value of the saturation magnetization measured by a VSM as a function of composition ratio agreed very well with the ones based on the theoretical calculation.