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The 3-[3α(2α-Hydroxy)pinane]-4,5-(pinan)-1,3-oxazolidine Synthesis, Structure and Properties
Bialek, Magdalena,Trzesowska, Agata,Kruszynski, Rafal Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.1
The new pinane derivative containing unique multifused ring system was synthesized. The crystal, molecular and electronic structure of the title compound has been determined. Both pinane ring systems have the same conformation. The five-membered oxazolidine ring exists in twisted chair conformation. The structure is expanded through O-H…O hydrogen bond to semiinfinite hydrogen-bonded chain. The bond lengths and angles in the optimised structure are similar to the experimental ones. The CH3 and CH2 groups (except this of oxazolidine ring) are negatively charged whereas the CH groups are positively charged. The largest negative potential is on the oxygen atoms. The C-N natural bond orbitals are polarised towards the nitrogen atom (ca. 61% at N) whereas the C-O bond orbitals are polarised towards the oxygen atom (ca. 67% at O). It is consistent with the charges on the nitrogen and oxygen atom of oxazolidine ring and the direction of the dipole moment vector (3.08 Debye).
Electronic Structure and Magnetism of CrP/SrBi Interface : A First Principles Study
Beata Bialek,Jae Il Lee 한국자기학회 2007 Journal of Magnetics Vol.12 No.3
We investigated the electronic structure and magnetic properties of zinc-blende CrP/SrBi interface by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. It is found that the half-metallicity is destroyed when the two half-metals are in contact. Magnetic moments of the atoms forming the supercell differ considerably from the respective values obtained for the bulk structures of the two materials. Cr atoms being and not being in contact with Bi atoms have magnetic moment 3.43 and 2.69 μB, respectively. Bi atoms lose their majority electrons which results in their negative polarization. Alkaline Sr atoms are very weakly negatively polarized. The spin distribution within the supercell is such that well separated regions of positive and negative polarization are seen, especially around the layer of P atoms being in contact with the layer of Sr atoms.
Beata Bialek,Jae Il Lee 한국자기학회 2015 Journal of Magnetics Vol.20 No.1
We investigated the half-metallicity and magnetism at the (001) and (110) surfaces of YC in zinc-blende structure by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. From the calculated local density of states, we found that neither (001) nor (110) surface preserves the half-metallicity. While the magnetic moment of Y atom in the YC bulk is 0.116 μB, it is 0.057 μB at the topmost layer of Y-terminated (001) surface. On the contrary, C-terminated (001) YC surface exhibits stronger magnetism than the bulk structure; the calculated magnetic moment on topmost C atom is 1.084 μB, while that of C atom in the bulk structure is 0.423 μB. The magnetic properties of the non-polar (110) YC surface are slightly enhanced as compared with the bulk structure.
The 3-[3α(2α-Hydroxy)pinane]-4,5-(pinan)-1,3-oxazolidine Synthesis, Structure and Properties
Magdalena Bialek*,Agata Trzesowska,Rafal Kruszynski 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.1
The new pinane derivative containing unique multifused ring system was synthesized. The crystal, molecular and electronic structure of the title compound has been determined. Both pinane ring systems have the same conformation. The five-membered oxazolidine ring exists in twisted chair conformation. The structure is expanded through O-H…O hydrogen bond to semiinfinite hydrogen-bonded chain. The bond lengths and angles in the optimised structure are similar to the experimental ones. The CH3 and CH2 groups (except this of oxazolidine ring) are negatively charged whereas the CH groups are positively charged. The largest negative potential is on the oxygen atoms. The C-N natural bond orbitals are polarised towards the nitrogen atom (ca. 61% at N) whereas the C-O bond orbitals are polarised towards the oxygen atom (ca. 67% at O). It is consistent with the charges on the nitrogen and oxygen atom of oxazolidine ring and the direction of the dipole moment vector (3.08 Debye).
Half-metallic and Magnetic Properties of (001) Surfaces of KCaN₂ Compound in full-Heusler Structure
Beata Bialek,Jae Il Lee 한국자기학회 2013 Journal of Magnetics Vol.18 No.4
The electronic and the magnetic properties of (001) surface of KCaN2 half-metallic compound with full-Heusler structure are studied with the use of a full-potential linearized augmented plane wave method. Two possible terminations of the surface are considered and only the one with N atoms in the topmost layer is found to retain the half-metallic properties of the bulk. The magnetic properties of N-terminated surface are enhanced compared with the properties of the bulk. The calculated magnetic moments on the N atoms in the KCaN₂ are 1.26 μB in the bulk and 1.90 μB at the surface. The subsurface metal atoms are also slightly polarized. In the surface terminated with metal atoms, not only the half-metallicity is destroyed, but also the magnetic properties of the system are weakened.
The Half-metallic Properties of (001) and (110) Surfaces of CsSe from the First-principles
Beata Bialek,Jae Il Lee 한국자기학회 2016 Journal of Magnetics Vol.21 No.1
We investigated the half-metallicity and magnetism at the (001) and (110) surfaces of CsSe in cesium chloride and zinc-blende structures by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. From the calculated local density of states, we found that all the surfaces preserve the half-metallicity of the bulk structures. The surfaces with a greater polarity have stronger ferromagnetic properties when terminated with Se atoms; the non-polar surfaces do not change their electronic or magnetic properties considerably as compared with the bulk structures.
(AlP)₁/(CrP)₁ 초격자계에서 (001) 표면의 자성과 반쪽금속성에 대한 제일원리 연구
Beata Bialek,이재일(Jae Il Lee) 한국자기학회 2015 韓國磁氣學會誌 Vol.25 No.6
The half-metallicity and magnetism of the (001) surfaces of (AlP)₁/(CrP)₁ superlattice were investigated by means of FLAPW (Fullpotential Liniarized Augmented Plane Wave) method. We considered four types of (001) surface termination, i.e., Al(S)-, Cr(S)-, P(S)Al(S-1)- and P(S)Cr(S-1)-term systems. We found that only Cr(S)-term system maintains the half-metallicity at the surface as only this system has the calculated magnetic moment of integer number of bohr magnetons. The magnetic moment of Cr(S) atom in the system was 3.02 μ<SUB>B</SUB> which was increased from the bulk value by the effects of band narrowing and increased spin-splitting at the surface. The electronic density of states of the P(S) atom in the P(S)Al(S-1)-term showed very sharp surface states due to the broken p<SUB>z</SUB> bonds at the surface. We found there is still a strong p-d hybridization between the P(S) and Cr(S-1) layers in the P(S)Cr(S-1)-term which causes a considerable increase of magnetic moment of P(S) atom.
Beata Bialek,Kalpana K. Landge,이재일(Jae Il Lee) 한국자기학회 2009 韓國磁氣學會誌 Vol.19 No.5
The effect of periodic vacancies to the magnetism of the Fe monolayer was investigated by calculating the electronic structures using the full-potential linearized augmented plane wave method within the GGA approximation. We considered four types of vacancies, point defect, I type, + type, and H type which are consisted of one, three, five and seven vacant sites, respectively. We found that the Fe atoms nearest to the vacancy have the largest magnetic moment in each system, and the value of magnetic moment of the atom was increased as the number of vacancy site is increased. The value of the largest magnetic moment in the systems of point defect, I type, + type, and H type are 3.08, 3.09, 3.15, and 3.30 bohr magnetons, respectively.
Beata Bialek,이재일 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.6
An all electron ab-initio method was emlpoyed to study the electronic and the magnetic properties of the (001) surface of alkaline-earth metal silicides, CaSi, SrSi, and BaSi, in the rock-salt structure. The three compounds retain their ferromagnetic metallic properties at the surface. Due to the surface effects, the magnetism of the topmost layer is changed as compared with the bulk. This is a short-range effect. In CaSi, the magnetism of the surface layer is noticeably reduced, as compared with the bulk: magnetic moments (MMs) on both Ca and Si atoms are reduced. In SrSi (001), the polarization of electrons in the surface atoms is similar to that in the bulk atoms, and the values of MMs on the component atoms in the topmost layer do not change as much as in CaSi. In BaSi (001), the magnetic properties of Si surface atoms are enhanced slightly, and the magnetism of Ba atoms is not affected considerably by the surface effect. The calculated densities of states confirm the short-range effect of the surface on the electronic properties of the metal silicides.