• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 동계학술연구발표회 및 스핀트로닉스와 나노물리에관한 국제심포지움
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• pp.108-109
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• 2007

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.148-149
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• 2002

In recent years, semiconductor spintronics has been rapidly developing due to potential device applications, in which the spin of charge carriers (electrons or holes) provides novel functionalities to carry signals and process information. Diluted magnetic semiconductors (DMSs) are well known to exhibit intriguing properties such as carrier-mediated ferromagnetism and spin-dependent transport resulting from the coupling between the charge transport states and the magnetic moments (spin) [1-3]. (omitted)

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제33회 하계학술대회 초록집
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• pp.278-278
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• 2007

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.103.1-103.1
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• 2008

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.88-88
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• 2009

$BiFeO_3$(BFO), when forming a solid solution with $BaTiO_3$(BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.7BFO-0.3BTO thin films on $Pt(111)/TiO_2/SiO_2/Si$ substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $600^{\circ}C$ and an oxygen partial pressure of 10mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with. the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron. microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• 한국세라믹학회지
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• 제43권2호
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• pp.79-84
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• 2006

We studied the microstructure and magnetic property of the pulsed DC magnetron sputtered $Zn_{\0.8}Co_{0.2}O$ film as a function of substrate temperatures. The X-ray patterns of the $Zn_{\0.8}Co_{0.2}O$ film showed a strong (002) preferential orientation at $500^{\circ}C$. The films with a crystallite size of 23-35 nm were grown in the form of nano-sized structure and this tendency was remarkable with increasing substrate temperature. The UV-visible result showed that the $Zn_{\0.8}Co_{0.2}O$ film prepared above $300^{\circ}C$ has a high optical transmittance of over $80\%$ in the visible region. The absorption bands were observed due to sp-d interchange action by $Co^{2+}$ complex ion and dd transition in the region from 500 to 700nm. The resistivity of the film was below $10^{-1}\;\Omega-cm\;above\;300^{\circ}C$. The AGM analysis results for the all films showed the magnetic hysteresis curves of ferromagnetic nature. The low electrical resistivity and room temperature ferromagnetism of ZnCoO thin films 'deposited above $300^{\circ}C$ suggested the possibility for the application to Diluted Magnetic Semiconductors (DMSs).

• Progress in Superconductivity
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• 제6권1호
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• pp.64-68
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• 2004

We fabricated cube-textured Ni and Ni-W alloy substrates for coated conductors and characterized the effects of W addition on microstructure, mechanical strength, and magnetic properties of the substrate. Pure Ni and Ni-(2, 3, 5at.%)W alloys were prepared by plasma arc melting, heavily cold rolled and then annealed at various temperatures of $600-1300^{\circ}C$. The texture was evaluated by pole-figure and orientation distribution function (ODF) analysis. Mechanical properties were investigated by micro Vickers hardness and tension test. Ferromagnetism of the substrate was measured by physical property measurement system (PPMS). It was observed that Ni-W substrates had sharp cube texture, and the full-width at half-maximums (FWHMs) of in-plane texture was $^{\circ}$-5.57$4.42^{\circ}$, which is better than that of pure Ni substrate. In addition cube texture of Ni-W substrates was retained at higher temperature up to $1300^{\circ}C$. Microstructural observation showed that the Ni-W substrates had fine grain size and higher mechanical properties than the pure Ni substrate. These improvements are probably due to strengthening mechanisms such as solid solution hardening and/or grain size strengthening. PPMS analysis showed that addition of W effectively reduced saturation magnetization in applied magnetic field and Curie temperature.

• 한국진공학회지
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• 제21권5호
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• pp.258-263
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• 2012

펄스레이저 증착법으로 P형 실리콘(100) 기판위에 증착한 Fe 희석된 Si 합금의 구조와 전기적 및 자기적 물성을 연구하였다. 합금시료에 대한 X-선 회절패턴에서 육방정계에 해당하는 FeSi, $Fe_3Si$, 및 $Fe_5Si_3$와 관련된 여러 개의 회절신호가 관측되었으며, 에너지분산분광 측정에 의한 시료내 Fe 원자의 함량은 1.25~6.49 atm, %로 나타났다. 또한, 온도변화에 따른 전기비저항 값의 측정으로부터 5.21 meV와 7.79 meV 두 개의 활성화에너지를 얻을 수 있었다. 절대온도 10 K에서 측정한 최대 자화는 약 100 emu/cc로 나타났으며, 3,000 Oe의 외부자기장하에서 온도의 함수로 측정한 자화 값으로부터 시료의 강자성 특성은 350 K까지도 유지됨을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.313-313
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• 2010

$BiFeO_3$ (BFO), when forming a solid solution with $BaTiO_3$ (BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.8 BFO-0.2 BTO thin films on Pt(111)/$TiO_2/SiO_2$/Si substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $700^{\circ}C$ and an oxygen partial pressure of 10mTorr and 330mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower and higher oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• 한국자기학회지
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• 제15권3호
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• pp.181-185
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• 2005

반응성 스퍼터링 방법으로 성장시킨 $Zn_{0.09}Cr_{0.01}O$ 묽은 자성반도체 박막의 구조와 전기 수송과 자기 특성에 미치는 Al 첨가 효과를 탐구하였다. Al이 첨가되지 않은 $Zn_{0.09}Cr_{0.01}O$ 박막은 반도체적인 수송 특성과 함께 미약한 강자성 특성을 보였다. Al을 첨가함으로써 n-형 나르개인 전자의 농도 증가와 더불어 금속성 수송 특성을 나타냈으며 포화자기화가 현저하게 증가하고 이력곡선이 뚜렷하게 나타나는 등 자기 특성의 격렬한 변화가 관찰되었다. 이 결과들은 Cr이 첨가된 ZnO에서 나르개에 의한 강자성 질서의 향상을 보여준다.