Magnetic Properties of New spin-Peierls-like Substances

从到1990年的两年时间里，我们合成了一些新的具有自旋-派尔斯相变的物质，并研究了它们的磁性质。(L)高质量有机盐晶体的制备合成了一些(菁染料-TCNQ)有机络盐，其磁性质表明存在自旋-派尔斯相变，并得到了高质量的单晶。(2)磁自旋磁化率的温度依赖性用法拉第方法测量了某些盐的自旋磁化率随温度的变化。其中两种盐类在低温下表现出异常。虽然高温下的磁化率可以用一维磁体模型很好地描述，但在低温下磁化率突然下降。(3)电子自旋共振(ESR)在盐类单晶中观察到ESR的单一吸收。吸收线宽强烈地依赖于温度和外加磁场的方向。磁化率的温度依赖性表明，在较低温度下存在自旋Peierls转变。然而，在该温度附近的ESR谱没有观察到异常。目前尚不清楚磁化率的突然下降是否会导致所谓的自旋-Peierls转变。(4)出版物这项研究的一部分已发表在J.Mag上。麦格。材料90&91(1990)241，标题为“有机离子自由基盐的磁性：DETzNC-[TCNQ]_2”。

Some new substances in which spin-Peierls transition seems to be observed were synthesized and their magnetic properties were investigated in two years from 1989 to 1990.(l) Preparation of high quality crystals of organic saltsSome (cyanine dye-TCNQ) organic complex salts of which magnetic properties suggest the presence of spin-Peierls transition were synthesized and their high quality single crystals were obtained.(2) Temperature dependence of magnetic spin-susceptibilityThe spin-susceptibility of some salts were measured as a function of temperature by Faraday method. Two of the salts show an anomaly at low temperatures. Though the susceptibility at high temperatures were well described by a model of one-dimensional magnet, it abruptly, decreases at low temperatures.(3) Electron spin resonance (ESR)A single absorption of ESR is observed in the single crystals of the salts. The linewidth of the absorption strongly depends on the temperature and the direction of applied magnetic field. The temperature dependence of the susceptibility suggests the presence of spinPeierls transition at a low temperature. However, no anomaly is observed in the ESR spectra near the temperature. It is not clear whether the abrupt decrease of the susceptibility results in so-called spin-Peierls transition.(4) PublicationsA part of this research have been published in J. Mag. Mag. Materials 90&91 (1990) 241 with the title "Magnetic Properties of an Organic Ion-Radical Salt : DETzNC-[TCNQ]_2".