Temperature effects in ion-electron emission of graphite quasicrystal

Effects of the deep ion-induced modification of highly oriented pyrolytic graphite

“…This is observed in the virtual absence of hysteresis and the agreement between the γ(Т) dependences measured in heating and cooling polycrystalline graphite MPG 8 [16]. The observed differences in the γ(Т) dependences measured in heat ing and cooling our HOPG samples indicated that the dynamic equilibrium conditions were not fulfilled and the formation of a thick altered layer is possible during irradiation.…”

“…This is demonstrated in Fig. 1, which shows (in addition to the first cycle of typical γ(Т) dependences taken from [16]) the γ(Т) dependences measured in the second heating-cooling cycle, performed without removing the altered layer formed in the first cycle. The electron yield peak at Т t observed in the second heating became smaller in size and wider in the temperature interval, while the γ(Т) dependence of the irradiated HOPG sample measured in cooling was close to the one determined in the first irradiation cycle.…”

“…The first results from measuring the γ(Т) depen dences in heating-cooling cycles for HOPG exceeded the expected hysteresis phenomena [16]. Analysis of the γ(Т) dependences measured when the temperature was varied from room temperature to 400°С and vice versa (the target was cooled under continuous irradia tion of the base UPV 1T plane using argon ions with an energy of 30 keV, normal to the surface) showed that the characteristic peak observed at texture transi tion temperature Т t = 150°С during target heating was not visible during cooling.…”

“…Measuring and analyzing the temperature depen dences of ion-electron emission is an efficient tech nique for in situ monitoring of ion induced structural and morphological changes in the surface layers of carbon materials [4,12,[14][15][16][17]. For example, the authors of [17] irradiated HOPG with argon ions and used the above method to determine the characteristic temperature T t of the ion induced texture transition.…”

“…The data on the first irradiation cycle were taken from[16].BULLETIN OF THE RUSSIAN ACADEMY OF SCIENCES. PHYSICS Vol.…”