Ferroelectric and Dielectric Properties of the Pb(Sc1/2Nb1/2)O3 Ceramic System

현준원,김연중,김강배,이기암,변재덕 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.3

This study examined the temperature dependence of the dielectric properties at various frequencies in the Pb(Sc1/2Nb1/2)O3(PSN) ceramic system with a perovskite structure produced using oxide mixing methods after sintering at 1420 ℃ for 15 minutes and at 1350 ℃ for 25 minutes. The ferroelectric properties of the PSN ceramic system were examined from the temperature dependence of the hysteresis loop by using a slight modification of the Sawyer-Tower circuit. The perovskite (1 1 0) to pyrochlore (2 2 2) ratio was determined by using X-ray diffraction, and the grain size of the sintered pellet was measured by field-emission scanning electron microscopy. The formation of sintered PSN was analyzed by energy dispersive X-ray spectroscopy.

Sputter로 제작된 BN박막의 물리적 특성

현준원,주종일 단국대학교 1999 論文集 Vol.34 No.-

We have studied annealing properties of Boron Nitride(BN) thin films. BN thin films were successfully grown on sillicon(100) substrate by rf magnetron sputter deposition. The effects of various annealing on BN thin films have been studied. The Fourier transform infrared absorption spectroscopy (FT-IR) of the depositied BN film (7000Å-1000℃-1-1hour) showed a strong absorption 1090 ㎝-1 clearly indication cubic structure. Surface roughness was observed by Atomic Force Microscope (AFM) and it shows that the roughness increase the phase of cBN. Using Dynamic ultra micro hardness tester, hardness of annealing BN thin film (7000Å-750℃-1-1hour) is about 4000 kgf/mm2 and it shows that it has the possibility of application as hard material. Therefore we conclude that the annealing temperature is related with formation of cBN phase.

Si/$SiO_2$/NiFe/$Al_2$$O_3$/Co 박막의 투과자기저항 특성 연구

현준원,백주열 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.11

Magnetic properties were investigated for Si/SiO$_2$/NiFe(300 )/A1$_2$O$_3$(t)/Co(200 ) junction related with the parameters of $Al_2$O$_3$. Insulating $Al_2$O$_3$ layer was formed by depositing a 5~40 thick Al layer, followed by a 90~120s RF plasma oxidation in an $O_2$ atmosphere. Magnetoresistance was not observed for tunnel junction with 5~10 thick Al layer, but magnetoresistance was observed large for tunnel junction with 15~40 thick Al layer. Oxidation time did not largely influence magnetoresistance. Tunnel magnetoresistance effect depended on magnetization behavior of two ferromagnetic layers. Tunneling junction was confirmed through nonlinear I-V curve. In this work, tunneling magnetoresistance(TMR) up to 30 % was observed. This apparent TMR is an artifact of the nonuniform current flow over the junction in the cross geometry of the electrodes.

Ferroelectric Properties of Bismuth-doped PMT-PT Ceramics

현준원,김연중,김강배 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.6

This study examined the ferroelectric properties of Bi-doped 0.66(Pb(1−3x/2) Bix)(Mg1/3 Ta2/3 O3-0.34PbTiO3 ceramics for use as a piezoelectric transformer. The optimum conditions for obtaining samples with high density and improved electrical properties were a sintering temperature of 1200 ℃/4 h and the addition of 3 mol% Bi. The temperature dependent dielectric constant of the ceramics was examined at frequencies ranging from 1 kHz to 100 kHz. The broad dielectric constant anomaly coupled with a shift in the dielectric maximum towards higher temperature with increasing frequency indicates a relaxor-type behavior in the ceramics. The piezoelectric coefficient (d33) and the planar coupling factor (Kp) increase with the addition of 3 mol% Bi, and then decrease with further addition of Bi. The dielectric constant and the dissipation factor at room temperature could be improved by the addition of 3 mol% Bi.

고온 고압 합성 다이아몬드의 제조와 합성 변수의 영향

현준원,김경례 단국대학교 1998 論文集 Vol.33 No.-

We have investigated the parameters for diamond particle size manufactured in high­pressure and high­temperature chambers of Belt. During synthesis, changes of synthesis parameters(temperature, pressure) and inclusions affect the diamond grains. Because the micro cracks containing much inclusions can decrease the particle size, a great number of diamond crystals synthesized in the wide range of p and T can be obtained as close to the diamond­graphite equilibrium line as possible.

Relaxor Ferroelectric Spectroscopy in Zr-doped PMT Binary Systems

현준원,박재웅,김연중 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.5

The dielectric and the relaxor properties at various frequencies in the solid solution (1 − x)Pb(Mg_(1/3)Ta_(2/3))O_3-xPbZrO_3 binary system were studied. The mixed oxide was prepared using columbite precursor methods and then sintering at 1200 ℃ for 2 hours. The grain sizes of the sintered specimens were measured and ranged from 1.6 ∼ 2.2 μm. The composition of 0.55Pb(Mg_(1/3)Ta_(2/3))O_3-0.45PbZrO_3 was found to have the maximum dielectric constant and remanent polarization, on the order of 27000 and 175 μC/cm^2, respectively. The relaxor ferroelectric (1 − x)Pb(Mg_(1/3)Ta_(2/3))O_3-xPbZrO_3 composition showed a large frequency dependence for the dielectric constant and loss. Also, the remanent polarization decreased gradually with increasing temperature, but did not vanish at the transition temperature.

유럽의 통합환경관리 제도현황 및 도입방향

현준원 한국폐기물자원순환학회(구 한국폐기물학회) 2014 한국폐기물자원순환학회 심포지움 Vol.2014 No.1

Electrical Response of Mixed Regions in the Pb(Mg1/3Ta2/3)O3 and the Pb(Mg1/3Nb2/3)O3 Complex Perovskites

현준원,김연중,노승정 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.8

The dielectric properties of the Pb(Mg1/3Ta2/3)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary systemswere examined as a function of temperature. The split (002) or (200) X-ray diffraction patternswere in the 2 range of 43.5 45.5 for xPb(Mg1/3Ta2/3)O3-(0.6-x)Pb(Mg1/3Nb2/3)O3-0.4PbTiO3indicating the formation of a tetragonal phase at room temperatures. The reciprocal dielectricconstant spectra were analyzed further in terms of normal and relaxor ferroelectrics. The frequencydispersion of the dielectric constant maxima was decreased by PbTiO3. From the dielectric datafor xPb(Mg1/3Ta2/3)O3-(0.7-x)Pb(Mg1/3Nb2/3)O3-0.3PbTiO3, two major anomalies correspondingto the rhombohedral ! tetragonal ! cubic phase transitions were observed. At a temperature ofabout 160 190 C, the dielectric constant deviates from the Curie-Weiss law and the deviationtemperature for normal ferroelectrics. The maximum values of the dielectric constant increased from21151 for 0.1Pb(Mg1/3Ta2/3)O3 to 29227 for 0.5Pb(Mg1/3Ta2/3)O3 for the xPb(Mg1/3Ta2/3)O3-(0.6-x)Pb(Mg1/3Nb2/3)O3-0.4PbTiO3 systems. However, the dielectric constant maxima between32626 at 0.1Pb(Mg1/3Ta2/3)O3 and 28757 at 0.3Pb(Mg1/3Ta2/3)O3 decreased with increasing molefraction x for the xPb(Mg1/3Ta2/3)O3-(0.7-x)Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 systems. The valueof the diffuseness component varied from 1.56 to 1.74 in Pb(Mg1/3Ta2/3)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary systems at different Pb(Mg1/3Ta2/3)O3 ratios.

환경질기준의 법적 성격과 초과의 법적 효과에 관한 소고 ― 독일의 대기환경질기준과 관련판례를 중심으로 ―

현준원 한국공법학회 2010 公法硏究 Vol.38 No.4

Für eine effektive Lösung dieser komplizierten Umweltprobleme ist es erforderlich, dass der Normgeber den Adressaten präzise Kriterien aufweist. Als ein probates Mittel dafür bieten sich die Umweltstandards an, nach denen die Adressaten zwischen zulässigem und unzulässigem Vorgehen einfach und deutlich unterscheiden können. Aus diesem Grund gewinnen technische und wissenschaftliche Standards im modernen Umweltrecht eine zunehmende Bedeutung. In der heutigen Zeit sind verschiedene Umweltstandards in Gesetzen, Verordnungen, Verwaltungsvorschriften oder sogar in privaten Regelungen festgesetzt. Die Umweltstandards kommen bei den Normsetzungen so zunehmend zur Anwendung, jedoch bilden sie unter öffentlich-rechtlicher Sicht ein schwieriges Problem zum Rechtsschutz für Umweltnutzungsinteressen und Umweltschutzinteressen. Unter Bezugnahme auf den Rechtsschutz der Bürger erzeugen sie insbesondere die Unparität des Rechtsschutzes zwischen den Bürgern, die Umweltnutzungsinteressen verfolgen, und den Bürgern, die Umweltschutzinteressen verfolgen. In den Fällen der Umweltgrenzwerte ist das Problem besonders bedeutend, weil sich die Überschreitung der Grenzwerte an unmittelbare Rechtsfolgen knüpft. Die Umweltnutzungsinteressen können dabei stets durch gerichtliches Vorgehen gegen diese Rechtsfolgen effektiv gewährleistet werden. Es ist hingegen fraglich, ob die Umweltschutzinteressen gerichtlich hinreichend geschützt werden. Deutlich wird diese Unparität des Rechtsschutzes zwischen den Bürgern, wenn sich beispielsweise die gerichtliche Aufhebbarkeit der bei der Grenzwertüberschreitung erlassenen Verkehrsbeschränkung durch die Bürger, die die betroffene Straße benutzen wollen, mit der Zulässigkeit einer Verpflichtungsklage gegen die trotz der Grenzwertüberschreitung untätig bleibende Behörde durch die Bürger, die in dem betroffenen Gebiet wohnen, vergleicht. Als ein repräsentatives Beispiel für die neuen Rechtsprobleme im Bereich des Rechtsschutzes für Umweltnutzungsinteressen und Umweltschutzinteressen gegen Umweltgrenzwerte haben die Immissionsgrenzwerte der deutschen 22. BImSchV in letzter Zeit unter Bezugnahme auf Feinstaubprobleme großes Aufsehen erregt. In Bezug auf diese Immissionsgrenzwerte und die Rechtsfolgen ihrer Überschreitung verdient eine Folge von jüngeren gerichtlichen Entscheidungen Beachtung. In den Rechtsprechungen steht die Frage im Mittelpunkt, ob ein Anspruch auf Aufstellung eines Aktionsplans und ein Anspruch auf eine konkrete Maßnahme zur Luftreinhaltung ohne Aktionsplan anerkannt werden können. In der Arbeit wird versucht, den Rechtscharakter der Immissionsgrenzwerte durch den Rechtsprechungen zu ermitteln. 환경법영역에서 수범자에게 허용되는 것과 허용되지 않는 것에 대한 명확한 판단기준을 제공함으로써 복잡한 환경문제를 효율적으로 해결하기 위하여 자주 사용되고 있는 수단이 바로 환경기준이다. 이러한 환경기준은 법적 명확성과 안정성, 아울러 효율적 문제해결에 있어서 중요한 의미를 갖고 있으나, 권리구제의 관점에서 전통적인 공법이론으로는 해결하기 어려운 난제를 가지고 있는 것도 사실이다. 특히 환경기준이 초과되었음에도 불구하고 부작위하고 있는 관할행정청에게 적극적으로 기준의 준수를 위하여 필요한 조치를 취하도록 요구할 수 있는 권리가 어디까지 인정될 수 있을 것인가에 대한 의문이 존재한다. 즉 전통적인 공법이론하에서 환경이용이익을 갖는 자에겐 자신의 환경오염행위에 대한 제재로 내려진 처분에 대하여 취소소송 등의 방법으로 침해된 자신의 권리를 회복할 수 있는 법적 수단이 상대적으로 넓게 마련되어 있으나, 환경보호이익을 갖는 자의 입장에선 환경기준의 초과에도 불구하고 부작위하고 있는 행정청에 대하여 행정개입이나 기준준수를 위한 행정계획의 수립 등을 요구하여 자신의 환경보호이익을 보호받을 수 있는 길을 인정받을 수 있는가에 대하여는 의문의 여지가 있다. 이러한 의문의 해답을 찾아보기 위하여 독일의 22. BImSchV상의 대기오염허용기준과 이를 초과하였음에도 불구하고 대기개선계획 등을 수립하지 않고 부작위하고 있는 행정청에 대하여 행정계획을 수립할 것을 청구한 뮌헨시의 사건을 중심으로 대기오염허용기준의 법적 성격, 환경기준이 초과되었음에도 불구하고 부작위하는 행정청에 대한 행정개입청구권 등의 인정여부 등에 대하여 검토하여 보았다.

Sputter로 제작된 BN박막의 물리적 특성

현준원 단국대학교 1999 論文集 Vol.34 No.-