| Research Abstract |
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.
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