• Advances in nano research
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• 제5권2호
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• pp.171-178
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• 2017

Superparamagnetic Zinc ferrite submicropheres are firstly synthesized via a one-pot solvothermal approach at $200-215^{\circ}C$ for 4-8 hours. $ZnCl_2$, $FeCl_3$ and NaAc are used as precursors with ethylene glycol solvent. The X-ray diffraction (XRD) data indicate that $ZnFe_2O_4$ nanoparticles with the grain size around $15{\pm}3nm$ can be successfully synthesized via the one-pot method. The scanning/transmission electronic microscope (SEM/TEM) images further show the samples are submicrospheres self-assembled by nanoparticles with size about 375-500 nm changed with reaction conditions. Room-temperature vibration magnetic strength measurements (VMS) demonstrates the as-obtained $ZnFe_2O_4$ submicrospheres show prefect superparamagnetism, whose coercivity force and remanence are practically nil. The reaction temperature and time influence on the crystallinity, diameter, saturated magnetic intensity and morphology of the particles.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.258-258
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• 2003

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.253-253
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• 2003

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2009년도 정기총회 및 동계학술연구발표회
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• pp.228-228
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• 2009

• Journal of Magnetics
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• 제3권3호
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• pp.96-98
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• 1998

In this paper a structurally coupled and magnetically decoupled Ba-ferrite thin film medium is proposed to evade the superparamagnetic limit and reduce media noise. The proposed medium consists of ferrimagnetic Ba-ferrite nano-grains (< 10 nm) and a non-magnetic grain boundary material. Magnetic grains are crystallographically matched with the grain boundary material. Spherical or cubic shaped Ba-ferrite particle is also proposed for above 100 Kfci particulate recording application.

• Journal of Magnetics
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• 제4권3호
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• pp.92-97
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• 1999

A relationship between microstructure and ferromagnetic resonance of Co/Ag multilayers has been studied in as-deposited and annealed multilayers iwth ultrathin (dCo < 1 nm) Co layers. Depending on the nominal thickness of Co Co/Ag multilayers represent a system of fine magnetic particles (dCo < 0.4 nm) or discontionuous layered structure (dCo/0.5 nm). FMR data has been interpreted in the framework of a odel of interacting fine particles exhibiting superparamagnetic behavior. Changes in the FMR spectra upon annealing have been attributed to the growth of the Co particles and to a transition from the fcc to hcp atomic structure of the highly (111) textured Co particles.

• 한국자기학회지
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• 제5권5호
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• pp.474-477
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• 1995

Granular Fe-SiO films were prepared by co-evaporating in a vacuum. Magnetic properties of the films were investigated by $M\"{o}ssbauer$ and magnetization measurments. The $M\"{o}ssbauer$ data suggest that the films consist of amorphous Fe-Si alloy particles with the size of nanometers. Superparamagnetic magnetization curves were well reproduced by considering the distribution of particle size and the magnetic dipole interaction between particles as the mean field.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.78.1-78.1
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• 2008

• 한국재료학회지
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• 제5권7호
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• pp.808-815
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• 1995

비화학량론적 치환형 페라이트 Fe$_{}1.429$(Al$_{4-x}$ Ga$_{x}$)$_{0.286}$ Si$_{0.143}$ /O$_4$계의 자기적 상태를 Mossbauer 분광법과 SQUID를 이용해 조사 하였다. 실온에서의 Mossbauer 스펙트럼은 x=0.2 경우 잘 정렬된 두개의 Zeeman 패턴을 보이고 x=0.4 경우 두개의 Zeeman 패턴과 이중선이 중첩되어 나타난다. 이중선의 근원은 치환 및 온도의존성을 고려할때 초상자성 cluster에 의한 것으로 보여지며 Neel's collinear모델과는 현저한 차이를 보이는 희석된 페라이트의 특성을 갖는다. 저온에서의 mossbauer 스팩트럼은 매우 다양한 형태를 보이며 초상자성 cluster의 freezing에 그 원인을 두고 있다. 그 영향으로 온도가 내려감에 따라 다임계적인 자기적 상태를 갖는다. SQUID 측정으로 얻어진 자화값이 50K 이하에서 급격히 감소하였는데 이것은 스핀 freezing과 초상자성 효과를 포함하는 스핀 canting의 효과로 설명되어 진다.

• Molecules and Cells
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• 제37권9호
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• pp.650-655
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• 2014

Mesenchymal stem cells (MSCs) can differentiate into neural cells to treat nervous system diseases. Magnetic resonance is an ideal means for cell tracking through labeling cells with superparamagnetic iron oxide (SPIO). However, no studies have described the neural differentiation ability of SPIO-labeled MSCs, which is the foundation for cell therapy and cell tracking in vivo. Our results showed that bone marrow-derived mesenchymal stem cells (BM-MSCs) labeled in vitro with SPIO can be induced into neural-like cells without affecting the viability and labeling efficiency. The cellular uptake of SPIO was maintained after labeled BM-MSCs differentiated into neural-like cells, which were the basis for transplanted cells that can be dynamically and non-invasively tracked in vivo by MRI. Moreover, the SPIO-labeled induced neural-like cells showed neural cell morphology and expressed related markers such as NSE, MAP-2. Furthermore, whole-cell patch clamp recording demonstrated that these neural-like cells exhibited electrophysiological properties of neurons. More importantly, there was no significant difference in the cellular viability and $[Ca^{2+}]_i$ between the induced labeled and unlabeled neural-like cells. In this study, we show for the first time that SPIO-labeled MSCs retained their differentiation capacity and could differentiate into neural-like cells with high cell viability and a good cellular state in vitro.