• Progress in Superconductivity
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• 제8권1호
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• pp.8-15
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• 2006

The size of the superconducting domains and the critical current density inside these domains have to be enhanced for most of cryomagnetic applications of melt-textured YBCO bulks. To enlarge the size of the domains we studied the multi-seeding technique based on a well-established procedure for preparing high quality YBCO monoliths using self-made SmBCO seeds. The distance between the seeds was optimised as a result of the investigation of the effects of various seed distances on the characteristics of the grain boundary Junctions. The influences of a-b plane intersections and c-axis misalignments were researched. Thereby, a small range of tolerance of the misorientations between the seed crystals was found. Field mapping was applied to control the materials quality and the superconductor's grain structure was investigated using polarisation microscopy. YBCO function elements with iou. seeds in a line and an arrangement of making type (100)/(100) and (110)/(110) boundary junctions, respectively, were processed. The trapped field profile in both sample types shows single domain behaviour. To demonstrate the potential of the multi-seeding method a ring-shaped sample was processed by placing sixteen seeds in a way to make both (100)/(100) and (110)/(110) grain junctions at the same time. The results up to now are very promising to prepare large single domain melt-textured YBCO semi-finished products in complex shapes.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.210-211
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• 2002

The magnetic anisotropy of amorphous wires plays a decisive role in the giant magnetoimpedance(GMI) behavior. The magnetoelastic anisotropy caused by internal stress, that are frozen in during the fabrication process, results in an axial easy axis in the core region and in a circular easy axis in the shell region [1]. It leads to a simple domain structure consisting of circular domains in the shell and axial domains in the core. For a more realistic domain structure, it has been suggested that the helical anisotropy exists due to an internal helical stress [2]. (omitted)

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.573-578
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• 2003

The structural, magnetic, and transport properties of a mono-layered manganite $La_{0.7}Sr_{1.3}MnO_{4+{\delta}}$ were investigated using variable temperature neutron powder diffraction as well as magnetization and transport measurements. The compound adopts the tetragonal I4/mmm symmetry and exhibits no magnetic reflection in the temperature region of 10 K ≤ T ≤ 300 K. A weak ferromagnetic (FM) transition occurs about 130 K, which almost coincides with the onset of a metal-insulator (M-I) transition. Extra oxygen that occupies the interstitial site between the [(La,Sr)O] layers makes the spacing between the [MnO₂] layers shorten, which enhances the inter-layer coupling and eventually leads to the M-I transition. We also found negative magneto resistance (MR) below the M-I transition temperature, which can be understood on the basis of the percolative transport via FM metallic domains in the antiferromagnetic (AFM) insulating matrix.

• 한국자기공명학회논문지
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• 제21권1호
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• pp.20-25
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• 2017

The cytoplasmic domains A and B of the mannitol transporter enzyme $II^{Mtl}$ are covalently linked in Escherichia coli, but separately expressed in Thermoanaerobacter Tengcongensis. The phosphorylation of domain B ($TtIIB^{Mtl}$) substantially increases the binding affinity to the domain A ($TtIIA^{Mtl}$) in T. Tengcongensis. To understand the structural basis of the enhanced domain-domain interaction by protein phosphorylation, we obtained NMR backbone assignments of the phospho-$TtIIB^{Mtl}$ using a standard suite of triple resonance experiments. Our results will be useful to monitor chemical shift changes at the active site of phosphorylation and the binding interfaces.

• 한국자기공명학회논문지
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• 제24권2호
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• pp.38-42
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• 2020

WW domains are small protein modules consisting of three-stranded antiparallel β-sheet, and involved in the protein-protein interaction for various biological systems. We overexpressed and purified WW2 domain from human AIP4/Itch (a member of Nedd4 family) using a pH/temperature dependent cleavage system. The backbone assignments of WW2 domain were completed, and secondary structure was predicted. Furthermore, backbone flexibility of WW2 domain was determined by ¹H-¹⁵N heteronuclear NOE and amide hydrogen exchange experiments. The structural information would contribute to the structural determination of WW2 domain as well as the interaction study of WW2 domain with various binding partners.

• 한국초전도ㆍ저온공학회논문지
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• 제21권4호
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• pp.6-8
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• 2019

Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning method.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.84-85
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• 2002

Recently doped perovskite manganites have renewed interest because they exhibit a variety of unique magnetic and electronic behaviors such as colossal magnetoresistance (CMR), percolative phase separation, spin/charge/orbital ordering, and so on. For this reason, fabrication of thin films with the best surface morphology and controlling their magneto transport properties is essential for making magneto-resistive devices. (omitted)

• Journal of Magnetics
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• 제7권1호
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• pp.9-13
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• 2002

The dependences of microscopic magnetic domain on film thickness in unidirectional and isotropic exchange-coupled NiO/NiFe bilayers were investigated by magnetic force microscopy to better understand for exchange biasing. As NiO thickness increases, microscopic domain structure of unidirectional biased film changed to smaller and more complicated domains. However, for isotropic-coupled film a new cross type domain appeared with out-of plane magnetization orientation. The density of the cross domain is proportional to exchange biasing fields and the fact that the domain was originated by the strongest exchange coupling region was confirmed from the dynamic domain configuration during a magnetization cycle.

• 한국세라믹학회지
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• 제32권3호
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• pp.313-320
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• 1995

We investigated the preferred orientation, electrical and magnetic properties of the Mn-Zn ferrite thin films deposited on SiO2/Si(100) by ion beam sputtering. The Cu-added Mn-Zn ferrite thin films had a preferred orientation of (111) with a weak orientation, (311). While the Zn-added one had a strong (111) preferred orientation. The saturation magnetization of the Cu- or Zn-doped Mn-Zn ferrite films increased with increasing substrate temperature (Ts) due to the increase of grain size and the enhancement of crystallinity. For the same reason the coercivity of Cu- or Zn-doped Mn-Zn ferrite films deposited at low Ts increased with increasing Ts, but those of the films deposited at high Ts slightly decreased not only because the defect density of the films decreases but because more grains have multi-domains with increasing Ts. The resistivity of Cu- or Zn-added Mn-Zn ferrite thin fims measured by complex impedance method decreased with increasing Ts due to the ehhancement of crystallinity as well as due to the increase of grain size.

• 한국자기공명학회논문지
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• 제20권4호
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• pp.102-108
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• 2016

With the rapid increase of data on protein-protein interactions, the need for delineating the 3D structures of huge protein complexes has increased. The protocols for determining nuclear magnetic resonance (NMR) structure can be applied to modeling complex structures coupled with sparse experimental restraints. In this report, I suggest the use of multiple rigid bodies for improving the efficiency of NMR-assisted structure modeling of huge complexes using CYANA. By preparing a region of known structure as a new type of residue that has no torsion angle, one can facilitate the search of the conformational spaces. This method has a distinct advantage over the rigidification of a region with synthetic distance restraints, particularly for the calculation of huge molecules. I have demonstrated the idea with calculations of decaubiquitins that are linked via Lys6, Lys11, Lys27, Lys29, Lys33, Lys48, or Lys63, or head to tail. Here, the ubiquitin region consisting of residues 1-70 was treated as a rigid body with a new residue. The efficiency of the calculation was further demonstrated in Lys48-linked decaubiquitin with ambiguous distance restraints. The approach can be readily extended to either protein-protein complexes or large proteins consisting of several domains.