| Project/Area Number |
17540336
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
NOGUCHI Satoru Osaka Prefecture University, Graduate School of Engineering, Associate Professor, 工学研究科, 教授 (70180718)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Takekazu Osaka Prefecture University, Graduate School of Engineering, Professor, 工学研究科, 教授 (00159732)
SUGIMOTO Toyonari Osaka Prefecture University, Graduate School of Science, Professor, 理学研究科, 教授 (30093256)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | organic magnetic semiconductors / ferromagnetism / antiferromagnetism / high field magnetization / magnetoconductance / 有機磁性半導体 |
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| Research Abstract |
1)We present clear evidence for ferromagnetic ordering in the magnetization data of (BEDT-TTFVS)・FeBr_4, which was newly synthesized as a semiconducting 1:1 charge-transfer salt. Magnetization data obtained by a resonant circuit method show a magnetic transition temperature of 1.9±0.3 K, and a hysteresis loop below 1.5 K. An additional magnetization jump at 0.2 T was clearly observed below 1.9 K, suggesting that the salt shows a canted ferromagnetism.
2)We observed magnetic orderings of Fe^<3+> d spins in the 1:1 salts of BEDT-TTFVS(O) with FeX_4 (X=Br,Cl) ions by magnetization measurements up to 0.5 T in the temperature range down to 0.4 K using a homemade pulsed magnet system combined with a ^3He cryostat. Although temperature dependences of the magnetic susceptibilities above 20 K obeyed a Curie-Weiss law with positive Weiss temperatures, the salts were not subjected to ferromagnetic ordering but to antiferromagnetic orderings except for (BEDT-TTFVS)・FeBr_4. The Neel temperatures, T_N were determined to be 2.4, 1.0 and 0.8 K for (BEDT-TTFV0)・FeBr_4, (BEDT-TTFVO)・FeCl_4 and (BELMTTFVS)・FeCl_4, respectively. Below T_N, a clear magnetization jump due to the spin-flop was also observed.
3)We performed high field magnetization measurements up to 55 T for newly synthesized antiferromagnetic charge-transfer salts, (Benzo-TTFVS)_2FeBr_4 with T_N=5.8 K and (Benzo-TTFVO)_2FeBr_4 with T_N=9.3 K A spin-flop behavior at 1.8 T and a saturation at 14.8 T were observed in the magnetization curve at 0.5 K for the (Benzo-TTFVS)_2FeBr_4 salt. For the (Benzo-TTFV0)_2FeBr_4 salt a spin-flop at 6.9 T and a saturation at 36.2 T were observed. We estimate the exchange interaction between d spins and the magnetic anisotropy for both salts from the magnetization data.
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