Magnetic Susceptibilities of TCNQ Complexes

概要

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The magnetic susceptibility (χ) of several highly conductive TCNQ complexes was measured in the temperature range from 2.5°K to room temperature. χ is composed of diamagnetic part (χ_d), a paramagnetic part (χ_c) caused by crystal imperfections, and an intrinsic paramagnetic part (χ_p). Three parts can be separated unambiguously, provided that χ_c obeys Curie's law and χ_p approaches zero as temperature is lowered. χ_p of Et_3NH(TCNQ)_2 below 300°K and that of DAD(TCNQ)_2 below 30°K are well explained by one triplet state per four TCNQ molecules at 310 cm^<-1> and 120 cm^<-1> above the ground singlet, respectively. Temperature dependence of χ_p of DAD(TCNQ)_2 from 30°K to 300°K cannot be explained quantitatively, though χ_p tends to coincide with that of undegenerated electron gas at high temperatures. For Q(TCNQ)_2, BiP(TBNQ)_2 and NMePh(TCNQ), χ were unsuccessfully separated, since χ_c deviated from the Curie's law owing to the high concentration of impurities in the samples. These results are discussed with the results of far infrared absorption spectra of these materials at 300°K and 1.5°K.
社団法人日本物理学会の論文
1969-08-05