Phase transitions in C70 at high pressure : A thermal conductivity study

• Measurements of the thermal conductivity lambda and the specific heat capacity per unit volume rhocv of polycrystalline C70 were carried out in the temperature range 100 - 450 K under pressures up to 1 GPa. Anomalies have been observed in lambda and rhocv near 300 K on cooling (increasing pressure) indicating a phase transition from a rotationally disordered phase into an ordered phase. The phase boundary for this transition was found to have a slope dT/dp = 70 K/GPa. The temperature dependence of lambda indicates a substantial amount of structural defects in the sample and strong hysteresis effects. We propose a phase diagram describing the probable evolution of orientational structure in T-p space.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Fullerenes

C70

phase diagram

high pressure

thermal conductivity

molecular orientation

Condensed matter physics

Kondenserade materiens fysik

fysik

Physics

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