Fundamental studies for high temperature organic ferromagnet

首先介绍了一种新的仪器--SQUID磁强计，并用标准样品对其性能进行了检验。然后，对一些TCNQ络合物的磁性进行了研究，因为据报道，这些络合物在室温下也表现出铁磁性。通过在Ar气氛下精心制备样品的多次实验，我们得出结论，已报道的铁磁性是错误的。为了发明有机亚铁磁体，我们还研究了几种稳定的基于硝基氮氧化物的双自由基的磁性。虽然在一些双自由基晶体上发现了有趣的磁性行为，但没有得到亚铁磁体。另一种高临界温度铁磁体的方法也在一些导电有机固体上进行了检验，但到目前为止还没有成功的结果。对这些线路的进一步调查是必不可少的。另一方面，对SQUID磁强计进行了改装，以测量电导率和磁阻随温度的变化情况，因为该仪器配备了良好的温度控制单元和高磁场电源。本次试验似乎是成功的，并将用于对一种磁电复合材料的进一步研究。

First of all, a new instrument (SQUID magnetometer) was introduced, and its ability was checked with a standard sample. Then, the magnetic properties of some TCNQ complexes were examined, because those complexes were reported to exhibit ferromagnetism even at room temperature. Several trials with carefully prepared samples under argon atmosphere led us to the conclusion that the ferromagnetism reported is erroneous, The magnetic properties of several stable biradicals based on nitronyl nitroxide were also investigated for the purpose to invent an organic ferrimagnet. Although interesting magnetic behavior was found on some biradical crystals, no ferrimagnet has been obtained. Another approach for a high critical temperature ferromagnet was also checked on some conducting organic solids, but no successful result has been observed until now. Further investigation on these lines is indispensable. On the other hand, the SQUID magnetometer has been modified for the measurements of temperature dependence of electrical conductivity and magnetoresistance, because the instrument is equipped with a good temperature control unit and a power supply for a high magnetic field. This trial seems to be successful and will be used further investigation on a magnetic-electrical composite materials.