Magnetic study on novel organic ferromagnetic semiconductors

新型有机铁磁半导体的磁性研究

• 批准号: 17540336
• 负责人: NOGUCHI Satoru
• 金额: $ 2.24万
• 依托单位: Osaka Prefecture University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17540336/
• 关键词: organic magnetic semiconductors; ferromagnetism; antiferromagnetism; high field magnetization; magnetoconductance; 有機磁性半導体

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.

（1）在新合成的半导体1：1电荷转移盐（BEDT-TTFVS）·FeBr_4的磁化强度数据中，我们给出了铁磁有序的明确证据。用谐振电路法测得的磁化强度数据表明，磁转变温度为1.9± 0.3K，磁滞回线低于1.5K。在低于1.9 K的温度下，我们清楚地观察到在0.2 T处的额外磁化强度跃变，这表明该盐显示出倾斜的铁磁性。2）我们使用自制的脉冲磁体系统结合^3He低温恒温器，在温度下至0.4 K的范围内，通过高达0.5 T的磁化强度测量，观察到了BEDT-TTFVS（O）与FeX_4（X=Br，Cl）离子的1：1盐中Fe^<3+> d自旋的磁有序。在20 K以上，磁化率的温度依赖性服从Curie-Weiss定律，外韦斯温度为正，但除（BEDT-TTFVS）·FeBr_4外，其它盐均不服从铁磁有序，而是反铁磁有序。测定了（BEDT-TTFV_0）·FeBr_4、（BEDT-TTFV_0）·FeCl_4和（BELMTTFVS）·FeCl_4的Neel温度T_N分别为2.4、1.0和0.8K。在T_N以下，由于自旋翻转而引起的明显的磁化跳变也被发现。3）我们对新合成的反铁磁电荷转移盐进行了高达55 T的高场磁化测量，（Benzo-TTFVS）_2FeBr_4，T_N= 5.8K，（Benzo-TTFVO）_2FeBr_4（T_N= 9.3K）在0.5K的磁化曲线上观察到1.8T的自旋翻转和14.8T的饱和。（Benzo-TTFVS）_2FeBr_4盐。对于（Benzo-TTFV_0）_2FeBr_4盐，观察到在6.9T下的自旋翻转和在36.2T下的饱和。我们估计的d自旋和磁各向异性的两种盐的磁化数据之间的交换相互作用。

项目成果

Magnetic orderings of Fe-3^+d spins in the 1:1 salts of BEDT-TTFVS(O) with FeX_4^_-(X=Br,Cl) ions

BEDT-TTFVS(O) 与 FeX_4^_-(X=Br,Cl) 离子的 1:1 盐中 Fe-3^ d 自旋的磁序

• 发表时间: 2007
• 期刊: J.Mag.Mag.Mater. 310
• 作者: S.Noguchi;et. al.
• 通讯作者: et. al.

A New Ferromagnetic Organic Semiconductor BEDT-TTFVS・FeBr_4

新型铁磁有机半导体BEDT-TTFVS·FeBr_4

• 发表时间: 2006
• 期刊: AIP Conf Proc. 850
• 作者: T.Hayakawa;et. al.;T.Hayashi et al.;H.Fujiwara et al.;S.Fujiyama et al.;T.Kusamoto et al.;S.Otsubo et al.;H.Fujiwara et al.;T.Konoike et al.;S.Noguchi et al.
• 通讯作者: S.Noguchi et al.

Metallic/semiconducting behaviors and antiferromagnetic ordering of FeBr_4^- d spins in (Benzo-TTFVS)_2・MX_4 (M=Fe, Ga; X=C1, Br)

(Benzo-TTFVS)_2・MX_4 (M=Fe, Ga; X=C1, Br) 中 FeBr_4^- d 自旋的金属/半导体行为和反铁磁有序性

• 发表时间: 2005
• 期刊: Journal of Materials Chemistry 15
• 作者: T.Hiraoka;Y.Kamada;T.Matsumoto;H.Fujiwara;T.Sugimoto;S.Noguchi;T.Ishida;H.Nakazumi;H.Aruga Katori
• 通讯作者: H.Aruga Katori

Metallic/semiconducting behaviors and antiferromagnetic ordering of FeBr_4^- d spins in (Benzo-TTFVS)_2 ・MX_4 (M = Fe, Ga ; X = Cl, Br)

(Benzo-TTFVS)_2 ・MX_4 (M = Fe, Ga; X = Cl, Br) 中 FeBr_4^- d 自旋的金属/半导体行为和反铁磁有序性

• 发表时间: 2005
• 期刊: Journal of Materials Chemistry 15
• 作者: T.Hiraoka;Y.Kamada;T.Matsumoto;H.Fujiwara;T.Sugimoto;S.Noguchi;T.Ishida;H.Nakazumi;H.Aruga Katori
• 通讯作者: H.Aruga Katori

High Field Magnetization of (Benzo-TTFVS)_2FeBr_4 and (Benzo-TTFVO)_2FeBr_4

(Benzo-TTFVS)_2FeBr_4 和 (Benzo-TTFVO)_2FeBr_4 的高场磁化

• 发表时间: 2006
• 期刊: J. Phys. : Conference Series 51
• 作者: S.Noguchi;A.Kuribayashi;T.Hiraoka;H.Fujiwara;T.Sugimoto;S.Kimura;M.Hagiwara;K.Kindo;T.Ishida
• 通讯作者: T.Ishida