Temperature-dependent electrical and magnetic properties of C22-Quinolinium(TCNQ) Langmuir-Blodgett films

Temperature-dependent electrical and magnetic properties of C22-Quinolinium(TCNQ) Langmuir-Blodgett(LB) films were investigated through a study of frequency-dependent dielectric constants and electron-spin resonance(ESR) measurements. The frequency-dependent dielectric constants of the thermally annealed C22-Quinolinium(TCNQ) LB films were measured in the frequency range of 10 Hz and 13 MHz. We have seen the effect of softening of the hydrophobic alkyl chains near 100 °C. The frequency-dependent dielectric constants show that there are two characteristic dispersions; one near 200 Hz and the other near 1 MHz. The angular dependent half-amplitude linewidth ΔH12 of the ESR signal measured at room temperature show that there is a minimum at around 54°, which indicates that the line broadening is possibly due to dipole-dipole interaction in the LB films. Temperature-dependent ESR signal shows that there is a big change in the signal above 80°C, which is also explained by the effect of softening of the alkyl chains.