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정우환
- 한국전기전자재료학회논문지
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- 제14권5호
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- pp.376-382
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- 2001
Magnetic and transport properties in the ceramic specimen of L $a_{0.7}$S $r_{0.3}$Fe $O_3$ with orthohombic structure has been investigated. Weak ferromagnetism has been observed in a ceramic sample of L $a_{0.7}$S $r_{0.3}$Fe $O_3$. Large dielectric relaxation of Debye type is observed in paramagnetic states within the temperature range of 130K~200K. From the temperature dependence of the characteristic frequency, we concluded that the elementary process of the dispersion is related to holes hopping between F $e^{3+}$ and F $e^{4+}$ ions. The temperature dependencies of thermoelectric power and Dc conductivity suggest that the charge carrier responsible for the conduction are strongly localized. These experimental results have been interpreted in terms of a hopping process involving small polaron.n.laron.n.
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Kang, Byung-Sub;Lee, Jae-Kwang;Lim, Yong-Sik;Song, Kie-Moon;Chae, Kwang-Pyo
- Journal of Magnetics
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- 제16권4호
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- pp.332-336
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- 2011
We studied the effect on the electronic and magnetic properties of the N defect in clean and Cu-doped wurtzite III-nitrides by using the first-principles calculations. When it is doped two Cu atoms in the nearest neighboring sites, the system of AlN, GaN, or InN with the N vacancy is energetically more favorable than that without the N vacancy site. When the Cu concentration increases, the total magnetic moment of a supercell becomes small. The ferromagnetism of Cu atom is very low due to the weak 3d-3d coupling. It is noticeable that the spin-exchange interaction between the Cu-3d and N defect states is important.
https://doi.org/10.4283/JMAG.2011.16.4.332 인용 PDF KSCI

Kim, Jeong-Seog;Cheon, Chae-Il;Park, Yong-Nam;Jang, Pyung-Woo
- 한국자기학회:학술대회 개요집
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- 한국자기학회 2002년도 동계연구발표회 논문개요집
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- pp.40-41
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- 2002
Synthesis of the ferroelectromagnetic material exhibiting ferromagnetism and ferroelectricity simultaneously has been an interesting subject due to not only for a possible application in electronic devices but also from the view point of solid state physics. In this study bulk ceramics and thin films of xBiFeO$_3$-yPrFeO$_3$-zPbTiO$_3$(x+y+z=1) and (1-w)BiFeO$_3$-wPbTiO$_3$ have been explored for finding ferroelectromagnetic material, in which ferroelectricity and ferromagnetism coexist simultaneously. (omitted)
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Lee, Sang Yoon;Jeong, Geumbi
- EDISON SW 활용 경진대회 논문집
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- 제5회(2016년)
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- pp.336-338
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- 2016
Recent multifunctional two-dimensional material research has triggered huge interests in various modifications for substitution of atoms. Instead of novel metals used as the most popular catalysts, nonprecious transition metals are promising candidates for efficient oxidation-reduction transfers. The recent discovery of $Co@C_2N$ has an alternate possiblity as catalysts for the ORR(Oxygen Reduction Reaction) in DSSc(Dye Sensitized Solar Cell) and OER(Oxygen evolution cobalt oxides). Here we report spin-polarized DFT calculations of the structure doped Iron that is one of ferromagnetism atoms like Co to provide a basic desciption of the ferromagnetism of the elemental metals. The spin-density-funtional results present the most stable state energetically is when having pairwise up/down spin.
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Y. H. Jeong;S-J. Han;Park, J.H.
- 한국자기학회:학술대회 개요집
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- 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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- pp.17-17
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- 2003
Semiconductors with ferromagnetism at room temperature has been actively searched for in recent years; a prospect of devices using both charge and spin continuously gives impetus to the activities. Transition metal doped oxide materials have been of particular interest. Co substituted ZnO [1] and TiO$_2$ [2] thin films, for example, were reported to show ferromagnetic properties at room temperature. However, various studies do not seem to converge on a definite picture [3,4,5]. The issue is rather fundamental: whether a system shows ferromagnetic properties at all, and in case it does, whether the system possesses a close coupling between magnetism and transport properties. In this talk, we shall assess the current status of transition metal doped oxide materials as room temperature ferromagnetic semiconductors.
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