• Title/Summary/Keyword: Diluted Magnetic Semiconductor

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MAGNETOTRANSPORT IN AN N-TYPE DILUTED MAGNETIC SEMICONDUCTOR: (Ga,Mn)N

  • Lee, K. I.;Lee, J. M.;J. Y. Chang;S. H. Han;Lee, W. Y.;M. H. Ham;J. M. Myoung
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.148-149
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    • 2002
  • In recent years, semiconductor spintronics has been rapidly developing due to potential device applications, in which the spin of charge carriers (electrons or holes) provides novel functionalities to carry signals and process information. Diluted magnetic semiconductors (DMSs) are well known to exhibit intriguing properties such as carrier-mediated ferromagnetism and spin-dependent transport resulting from the coupling between the charge transport states and the magnetic moments (spin) [1-3]. (omitted)

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Ferromagnic Transitition Temperature of Diluted Magnetic III-V Based Semiconductor (III-V 화합물 자성 반도체의 강자성체 천이온도에 관한 연구)

  • Lee, Hwa-Yong;Kim, Song-Gang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.143-147
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    • 2001
  • Ferromagnetism in manganese compound semiconductors open prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds. Also it addresses a question about the origin of the magnetic interactions that lead to a Curie temperature(Tc) as high as 110 K for a manganese concentration of just 5%. Zener's model of ferromagnetism, originally suggested for transition metals in 1950, can explain Tc of $Ga_{1-x}Mn_x$ As and that of its IT-VI counterpart $Zn_{1-x}Mn_x$ Te and is used to predict materials with Tc exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin. In this article, we present not only the experimental result but calculated Curie temperature by RKKY interaction. The problem in making III-V semiconductor has been the low solubility of magnetic elements, such as manganese, in the compound, since the magnetic effects are roughly proportional to the concentration of the magnetic ions. Low solubility of magnetic elements was overcome by low-temperature nonequilibrium MBE{molecular beam epitaxy) growth, and ferromagnetic (Ga,Mn)As was realized. Magnetotransport measurements revealed that the magnetic transition temperature can be as high as 110 K for a small manganese concentration.

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Ferromagnetic Properties in Diluted Magnetic Semiconductors (Al,Mn)N grown by PEMBE

  • Ham, Moon-Ho;Myoung, Jae-Min
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.1
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    • pp.12-15
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    • 2006
  • We present the structural, magnetic, and electrical properties in the (Al,Mn)N films with various Mn concentrations grown by plasma-enhanced molecular beam epitaxy. X-ray diffraction analyses reveal that the (Al,Mn)N films have the wurtzite structure without secondary phases. All (Al,Mn)N films showed the ferromagnetic ordering. Particularly, ($Al_{1-x}Mn_{x}$)N film with x = 0.028 exhibited the highest magnetic moment per Mn atom at room temperature. Since all the films exhibit the insulating characteristics, the origin of ferromagnetism in (Al,Mn)N might be attributed to either indirect exchange interaction caused by virtual electron excitations from Mn acceptor level to the valence band within the samples or a percolation of bound magnetic polarons arisen from exchange interaction of localized carriers with magnetic impurities in a low carrier density regime.

Structural, Electrical and Magnetic Properties of Wide Bandgap Diluted Magnetic Semiconductor CuAl1-xMnxO2 Ceramics (널은 띠간격 묽은 자성반도체 CuAl1-xMnxO2 세라믹스의 구조 및 전자기 특성)

  • Ji Sung Hwa;Kim Hyojin
    • Korean Journal of Materials Research
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    • v.14 no.8
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    • pp.595-599
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    • 2004
  • We investigated the structural, electrical and magnetic properties of Mn-doped $CuAlO_2$ delafossite ceramics ($CuAl_{1-x}Mn_{x}O_2,\;0\le\;x\;\le0.05$), synthesized by solid-state reaction method in an air atmosphere at a sintering temperature of $1150^{\circ}C$. The solubility limit of Mn ions in delafossite $CuAlO_2$ was found to be as low as about 3 $mol\%$. Positive Hall coefficient and the temperature dependence of conductivity established that non-doped $CuAlO_2$ ceramic is a variable-range hopping p-type semiconductor. It was found that the Mn-doping in $CuAlO_2$ rapidly reduced the hole concentration and conductivity, indicating compensation of free holes. The analysis of the magnetization data provided an evidence that antiferromagnetic superexchange interaction is the dominant mechanism of the exchange coupling between Mn ions in $CuAl_{1-x}Mn_{x}O$ alloy, leading to an almost paramagnetic behavior in this alloy.

Structural, Optical, and Magnetic Properties of Si1-xMnxTe1.5 Single Crystals (Si1-xMnxTe1.5 단결정의 구조적, 광학적, 자기적 특성에 관한 연구)

  • Hwang, Young-Hun;Um, Young-Ho;Cho, Sung-Lae
    • Journal of the Korean Magnetics Society
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    • v.16 no.3
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    • pp.178-181
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    • 2006
  • We have investigated the Mn concentration-dependent structural, optical, magnetic properties in IV-VI diluted magnetic semiconductor $Si_{1-x}Mn_xTe_{1.5} $ crystals prepared by the vertical Bridgman technique. X-ray studies showed the single crystalline hexagonal crystal structure. From the optical absorption measurements energy band gap were found to decreases with increasing x and temperature. From the magnetization measurements the samples had ferromagnetic ordering with Curie temperature $T_C$ about 80 K. With increasing Mn concentration, the average magnetic moments per Mn atom determined from the saturated magnetization increased.

A Study on the Properties of the Magnetic Semiconductor GaMnAs Depending on Thin Film Deposition and the Treatment Conditions (GaMnAs 자성반도체의 박막 특성 및 후처리에 따른 특성 변화 연구)

  • Kim, Dong-Sik
    • 전자공학회논문지 IE
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    • v.45 no.3
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    • pp.1-4
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    • 2008
  • We investigate magnetic semiconductor thin films for application towards spintronics, which can overcome current limitations in semiconductor devices. GaMnAs magnetic semiconducting films studied are easily integrated into conventional semiconductor processes and also offer a wide range of application, therefore it shows much promise as a future material. However the Curie temperature at which magnetic properties exist for GnMnAs is very low, also depending on deposition conditions the properties of the film can vary widely. In order to study these issues we investigate the best possible deposition conditions for magnetic properties.

Room temperature ferromagnetism in diluted magnetic semiconductor $Zn_{l-x}Cr_xTe$

  • Ando, K.;Saito, H.;Zayets, V.;Yamagata, S.
    • Proceedings of the Korean Magnestics Society Conference
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    • 2003.06a
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    • pp.266-267
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    • 2003
  • The most distinguishing character of diluted magnetic semiconductors (DMSs) is a strong interaction between sp-carriers and localized d-spins (sp-d exchange interaction). Recently many "room-temperature (RT) ferromagnetic DMS" have been reported. However, it should be noted that their sp-d exchange interactions have not been confirmed yet. The lack of a clear evidence of the sp-d exchange interaction causes the controversy on the origin of the observed ferromagnetism. For the detection of the sp-d exchange interaction, magneto-optical spectroscopy such as a magnetic circular dichroism (MCD) measurement is the most powerful tool. By using the MCD spectroscopy, we have shown the sp-d exchange interactions in Zn$_{l-x}$Cr$_{x}$Te. Recently, we have obtained the RT ferromagnetism in a Zn$_{l-x}$Cr$_{x}$Te (x = 0.20) film.0) film.

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