Electron spin resonance and microwave photoconductivity in carbynoid films

First ESR studies are reported on oriented carbynoid samples prepared by ch emical dehydrofluorination of poly(vinylidene fluoride) films. Two types of paramagnetic centres (PC), denoted as C-M1 and C-M2, and an anisotropic br oad line were detected. The spectra of the PC C-M1 are isotropic with a g-v alue of 2.0045 +/- 0.0003. The absorption by given PC is well saturated at room temperature and the PC C-MI can be attributed either to free radical s tates or pinned quasi-particles similar to topological Su-Schrieffer-Heeger solitons. The ESR and microwave photoconductivity results obtained confirm the quasi- 1D nature of the carbon chains, being the structural elements of the sample s studied, and agree with the assumption that the ground state of carbon ch ains is a state with a spin density wave (SDW) realized at room temperature . The ESR spectrum of the PC C-M2 consisting of a series of unsaturated lines is anisotropic both in relation to the static magnetic field and in relati on to the magnetic component of the microwave field. The study of the inter action dynamics of the microwave field with PC C-M2, the absorption depende nce with increase of the microwave field and the temperature dependence all ow us to attribute the PC C-M2 to mobile quasi-particles, being domain wall s in the alternated spin density distribution, tentatively solitons in the SDW. It has been found that spin waves associated with the PC C-M2 can be observ ed in samples treated thermally at 120 degrees C for 2 hours (the samples c ontained fluorine with atomic ratio F/C = 3/7 and oxygen at 20 at.%). It has been proven that the spin waves' excitation and the formation of qua si-particles like solitons can represent the same process.