engleski

Thermal and thermoelectric properties of icosahedral Al62Cu25.5Fe12.5 quasicrystal

Experimental results on thermal and thermoelectric properties of icosahedral i-Al62Cu25.5Fe12.5 quasicrystal in temperature range 4.2 K-340 K are examined, and comparison with icosahedral i-Al63Cu25Fe12 quasicrystal is made. The results of thermoelectric properties can be consistently explained by a two band model. Although the picture that overlapping of the valence and the conduction bands at Fermi level is responsible for the coexistence of both types of carriers enable us to describe quasicrystals as semi-metals. The phonon thermal conductivity increases monotonically with temperature showing a shallow maximum at about 25 K, followed by a minimum around 70 K, and a subsequent increase. The shallow maximum in phonon thermal conductivity could be interpreted as a crossover from the regime of a dominant scattering on tunneling states of an unspecified nature to the regime where quasiperiodic Umklapp process are important.

disordered systems; phonon thermal conductivity; electrical conductivity; thermoelectric power; Hall coefficient

Rad je kao poster Ana Smontara prezentirala na skupu The 7th International conference on quasicrystals (ICQ7), održanom od 20.-24.09.1999., Stuttgart, Njemačka ; objavljen u Zborniku (S.I.).