THE PHASE DIAGRAM OF NEW ORGANIC SUPERCONDUCTOR BETS SALTS WITH A MIXED HALIDE GALLIUM ANION

新型有机超导体与混合卤化镓阴离子的盐相图

• 批准号: 08454217
• 负责人: KOBAYASHI Akiko
• 金额: $ 3.58万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454217/
• 关键词: molecular superconductor; phase diagram; BETS; organic superconductor

In 1996, crystal structures, electrical resistivities and magnetic susceptibilities of a series of organic superconductors with tetrahedral mixed halide gallium anions, lambda-BETS2GaXzY4-z (X,Y=F,Cl, Br ; 0<z<4) having triclinic unit cells and fourfold quasi-stacking arrangement of BETS (=bis (ethylene-dithio) tetraselenafulvalene) molecules were examined. The resistivity behavior dependedon the size of anion. The superconducting behavior could be examined systematically by exchanging the halogen atoms (X,Y) and the z-value. The magnetic susceptibilities were studied on lambda-BETS_2GaCl_3F and lambda-BETS_2GaBr_zCl_<4-z> (0<z<1.5). Although the resistivity behaviors of lambda-BETS_2GaX_zY_<4-z> resemble closely those of so-called 10K-class kappa-type BEDT-TTF superconductors, the insulating ground state near the superconducting state is non-magnetic. Theoretically this non-magnetic phase is pointed out that it has the possibility of exsisting on the borderline of spin-gap phase and antiferromagnetic phase. This year this non-magnetic phase was examined precisely by ^1H-NMR.^1H-NMR did not exhibit the abrupt increase of 2nd moment, which was observed in kappa-(ET)_2[CuN(CN)_2]Cl. In lambda-(BETS)_2GaCl_<2.5>Br_<1.5> the divergence of 1/T_1 which is characteristicin forming the magnetic orderness was not observed within the temperature range from 25K to 2K.So this phase is considered not as antiferromagnetic phase but as non-magnetic phase. lambda'-BETS3GaBr4 has a modified lambda-type structure and it shows narrow-gap semiconducting behavior down to 50K.lambda'-BETS3GaBr4 transforms to the insulating phase below 50 K.The decrease of magnetic susceptibilities with the anisotropies parallel to H and perpendicular to H was observed below 60 K.This phase transition seems to be antiferromagnetic. Such a high temperature antiferromagnetic phase transition of organic molecules is very rare and very interesting, compared with high-temperature inorganic superconductors.

1996年，我们研究了一系列四面体混合卤镓阴离子的有机超导体：具有三斜晶系晶胞和四重准堆积排列的BETS（=二（亚乙基二硫代）四硒富瓦烯）分子的BETS_2GaX_zY_（4-z）（X，Y=F，Cl，Br ; 0<z<4）的晶体结构、电导率和磁电阻率。电阻率行为与阴离子的尺寸有关。通过卤素原子（X，Y）和z值的交换，可以系统地考察超导行为。本文研究了Ba-BETS_2GaCl_3F和Ba-BETS_2GaBr_zCl_<4-z>（0&lt;z&lt;1.5）的磁化率。虽然BEDTA-BETS_2GaX_zY_2的电阻率行为<4-z>与所谓的10 K级kappa型BEDT-TTF超导体的电阻率行为非常相似，但超导态附近的绝缘基态是非磁性的。理论上指出这种非磁性相存在于自旋能隙相和反铁磁相的交界处。今年，这种非磁性相通过^1H-NMR进行了精确的检测。~ 1H-NMR没有发现kappa-（ET）_2[CuN（CN）_2]Cl中出现的二阶矩的突然增加。在λ-（BETS）_2GaCl_Br_2中<2.5>，在<1.5>25 - 2K温度范围内没有观察到形成磁取向的特征1/T_1发散，因此认为该相不是反铁磁相，而是非磁相。Alxda '-BETS 3GaBr 4具有改进的Alxda-BETS 3GaBr 4型结构，在50 K以下表现出窄禁带半导体行为。Alxda'-BETS 3GaBr 4在50 K以下转变为绝缘相。在60 K以下观察到平行于H和垂直于H的各向异性的磁性下降。与高温无机超导体相比，有机分子的这种高温反铁磁相变是非常罕见和非常有趣的。

项目成果

Hayao.Kobayashi: "Superconductor-to-Insulctor Transition an Organic Metal Incorporating Magnetic Anions:λ-(BETS)_2FexGaCl_4-x" Jounal of American Chemical Society. 119. 12392-12393 (1997)

Hayao.Kobayashi：“结合磁性阴离子的有机金属的超导体到绝缘体的转变：λ-(BETS)_2FexGaCl_4-x”美国化学会杂志 119. 12392-12393 (1997)。

Madaka Tokumoto: "Magnetic Anisotropy of Organic Conductors lambda-(BETS)_2FeC ; _4" Synthetic Metals. 86. 2161-2162 (1997)

Madaka Tokumoto：“有机导体的磁各向异性 lambda-(BETS)_2FeC；_4”合成金属。

Akiko.Kobayashi: "κ-type Molecular Arrangements and Electrical Ressistirties of (BETS)_2InCl_4、BETS_2ClO_4(TCE)_<0.5> and (BETS)_2[(C_2H_5)_4N]_<0.7>InCl_5" Molecular Crystals and Lignid Crystals. 296. 181-195 (1997)

Akiko.Kobayashi：“(BETS)_2InCl_4、BETS_2ClO_4(TCE)_<0.5> 和 (BETS)_2[(C_2H_5)_4N]_<0.7>InCl_5 的 κ 型分子排列和电阻”分子晶体和木质素晶体。 296. 181-195 (1997)

Hayao Kobayashi: "Superconductor-to Insulator Transition in an Organic Metal Incorporating Magnetic Anions : lambda-(BETS)_2Fe_xGa_<1-x>Cl_4" J.Amer.Chem Soc.119. 12392-12393 (1997)

Hayao Kobayashi：“结合磁性阴离子的有机金属中的超导体到绝缘体的转变：lambda-(BETS)_2Fe_xGa_<1-x>Cl_4”J.Amer.Chem Soc.119。

Hiroki.Akutsu: "Highly Correlented Organic Conductor with magnet Anions Exhibiting a π-d Coupled Metal-Insulator Transition λ-(BETS)_2Br_<rλ>Cl_4-x" Jounal of American Chemical Society. 119. 12681-12682 (1997)

Hiroki.Akutsu：“具有 π-d 耦合金属-绝缘体跃迁 λ-(BETS)_2Br_<rλ>Cl_4-x 的磁铁阴离子的高度相关有机导体”美国化学会杂志 119。12681-12682 (1997)。