GROWTH-CHARACTERISTICS OF SPUTTER-DEPOSITED UPT3 THIN-FILMS

Thin films of the heavy-fermion superconductor UPt3 were deposited on various substrate materials in various orientations by means of a quas i-multilayer sputter process. Strongly (0001)-textured growth of the h exagonal compound was found for a uranium content in the range of 23% to 28% on sapphire (<10(1)over bar 2>), LaAlO3(111) and SrTiO3(lll) wi th perfect in-plane order on the latter substrate material. Atomic for ce microscopy and scanning electron microscopy revealed a Vollmer-Webe r-like growth mode resulting in the development of large compressive s train in films on SrTiO3(111). As a result the electronic transport pr operties-in particular the temperature dependence of the resistivity-w ere strongly renormalized. Strong deviations from the typical heavy-fe rmion characteristics known from UPt3 bulk samples were found in films on SrTiO3 with residual resistance ratios rho(300 K)/rho(0) up to 930 and a significantly reduced superconducting transition temperature of 130 mK.