• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.423-426
• /
• 2001

Recently we have reported that the meander-patterned amorphous FeCoSiB films exhibit large change in their high frequency impedance by applying a strain, suggesting that the films are very attractive for making of a highly sensitive strain sensor elements. In this study, the effect of anisotropy on a change in the impedance of sputtered amorphous film patterns was investigated in the frequency range from 1MHz to 1GHz. As a function of applied strains, the high frequency impedance was extremely changed in the case of film patterns with transverse anisotropy due to excellent magnetomechanical coupling properties. As a summary, the maximum figure of merit f has measured about 2600 in the case of transverse anisotropy, and about 500 in the case of longitudinal anisotropy at 500 MHz. These values of F are approximately more than 1000 times higher than that of a conventional metal strain gauge (F 2) and more than 10 times higher than that of a semiconductor gauge (F 200).

• Journal of Magnetics
• /
• 제18권1호
• /
• pp.5-8
• /
• 2013

The perpendicular magnetic anisotropy of sputtered CoFeB thin films covered by MgO was investigated by vibrating sample magnetometry. Three different $Co_xFe_{80-x}B_{20}$ alloys were studied. Under out-of plane magnetic field, the saturation field was found to increase with increasing the Co content. The magnetization and interface anisotropy energy were obtained for all samples. Both showed a marked dependence on the MgO overlayer thickness. In addition, their variations were found to be non-monotonous as a function of the Co concentration.

• 한국광학회지
• /
• 제26권2호
• /
• pp.115-120
• /
• 2015

광축의 각도가 서로 다른 두 단축이방성 박막이 다층박막 기층시료 위에 코팅되어 있을 때 비스듬히 입사한 빛의 유효반사계수 표현들을 유도하였다. 유효반사계수로부터 타원상수 표현들을 구하고 이 타원상수의 단축이방성 박막 광축각도 의존성으로부터 단축이방성 박막의 표면 이방성에 의한 효과와 주층 이방성에 의한 효과를 구분하여 해석할 수 있도록 하였다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 추계학술대회 논문집
• /
• pp.301-303
• /
• 2008

In order to investigate the influence of anisotropy on formability and also to obtain guidelines for the stamping process design in friction stir welded TWB (tailor welded blank), the aluminum ally 6111-T4 sheet was welded with three different types of combination: RD||RD, TD||RD and TD||TD (Here, RD and TD mean the rolling direction and transverse direction, respectively) and then hemisphere dome stretching and cylindrical cup drawing tests were carried out. In addition, the numerical analysis was performed to confirm the validity of experimental results. For the numerical analysis, the non-quadratic orthotropic yield function, Yld2004-18p was utilized to represent precise anisotropic properties.

• Computers and Concrete
• /
• 제5권4호
• /
• pp.417-434
• /
• 2008

This paper deals with damage induced anisotropy modeling for concrete-like materials. A thermodynamics based constitutive relationship is presented coupling anisotropic damage and elasticity, the main idea of the model being that damage anisotropy is responsible for the dissymmetry tension/compression. A strain written damage criterion is considered (Mazars criterion extended to anisotropy in the initial model). The biaxial behavior of a family of anisotropic damage model is analyzed through the effects of yield surface modifications by the introduction of new equivalent strains.

• 대한전자공학회논문지
• /
• 제21권4호
• /
• pp.17-23
• /
• 1984

A model analysis of pattern shift in the epitaxial growth of silicon on (111) substrates was performed. The growth rate anisotropy was considered as the most important affecting factor of pattern shift, and for the model establishment the off angle of the substrate and the process temperature were taken as the variables. We derived a theoretical equation of pattern shift by assuming the growth rate anisotropy as the trigonometric sine function of the off angle of the substrate and defining the growth rate anisotropy factor related to the process temperature. The pattern shift ratio calculated by this model had the same tendency with the experimental ones, which, however, were about twice greater than those. It was supposed that this discrepailcy was due to the second order affecting factor such as facetting and step broadening which had been exluded in model establishment.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.681-686
• /
• 2004

Identification of asymmetry and anisotropy of rotor system is important for diagnosis of rotating machinery. Directional frequency response functions (dFRFs) are known to be powerful tool in effectively detecting the presence of asymmetry or anisotropy. In this paper, an estimation method of dFRFs for rotors is newly developed, when both asymmetry and anisotropy are present. The method transforms the finite degrees-of-freedom time-varying linear differential equation of motion to an infinite degree-of-freedom time-invariant linear one, employing the modulated coordinates. The validity of the method is demonstrated by numerical simulation with a simple rotor model.

• Journal of Magnetics
• /
• 제9권4호
• /
• pp.121-124
• /
• 2004

NiO thickness dependences of perpendicular magnetic anisotropy (PMA) in the $NiO/[CoFe/Pt]_5$ multilayers for exchange biasing and $[CoFe/Pt]_4/Pt/[CoFe/Pt]_4$ for interlayer exchange coupling were investigated. Perpendicular magnetization curve was obtained by out-of-plane extraordinary Hall measurement. Magnetic force microscopy (MFM) has been used for the investigation of magnetic domains on thin films. We confirmed that the interlayer exchange coupling (IEC) as a function of NiO thickness at room temperature existed with a period of two monolayers.

• Journal of Magnetics
• /
• 제10권2호
• /
• pp.44-47
• /
• 2005

The oscillatory interlayer exchange coupling (IEC) has been shown in pinned $[CoFe/Pt(t_{pt})/CoFe]/IrMn$ multi-layers with perpendicular anisotropy. The period of oscillation corresponds to about 2 monolayers of Pt. The oscillatory behavior of IEC depending on the nonmagnetic metallic Pt thickness is thought to be related the antiferromagnetic ordering induced by IrMn layer. Oscillatory IEC as function of insulating NiO thickness has been observed in $[Pt/CoFe]_4/NiO(t_{NiO})/[CoFe/Pt]_4$ multilayers. The effect of N (number of bilayer repeats) upon the magnetic property of [Pt/CoFe]N/IrMn is also studied.

• 한국광학회지
• /
• 제27권6호
• /
• pp.223-228
• /
• 2016

액정과 같은 단축 이방성 분자들의 정렬 정도에 따라 달라지는 복굴절으로부터 상대 복굴절 ${\Delta}n_{rel}$를 구하고 ${\Delta}n_{rel}$과 방향질서변수(orientational order parameter) S의 관계를 탐색하였다. 무질서한 분포를 하고 있는 경우를 포함하여 액정의 정렬정도를 달리 표현할 수 있는 분포함수를 도입하고 이 분포함수를 사용하여 질서변수 S가 0부터 1까지 변하도록 액정분자들의 정렬정도를 달리하며 ${\Delta}n_{rel}$과 S를 수치계산 하였다. 이 계산 결과로부터 s와 ${\Delta}n_{rel}$는 $S=(1+a){\Delta}n_{rel}-a{\Delta}n^2_{rel}$와 같이 준선형적인 관계를 만족하며 a는 $n_o{\frac{{\Delta}n}{4}}$으로 근사할 수 있음을 확인하였다. 또한 복굴절으로부터 Vuks의 방법에 따라 구한 분자분극의 이방성과 Neugebauer의 방법에 따라 구한 분자분극의 이방성이 각각 질서변수 S와 또 다른 준선형 관계식들을 따름을 보였다.