Thin films of Ln_(1-x)Sr_xCoO_3 (Ln = La, Nd and Gd) and SrRuO_3 by nebulized spray pyrolysis

摘要

Thin films of Ln_(1-x)Sr_xCoO_3, Nd_(0.5)Sr_(0.5)CoO_3, Gd_(0.5)Sr_(0.5)CoO_3 and SrRuO_3 have been deposited on Si(l00), LaAlO_3(l00) and SrTiO_3(l00) single crystal substrates by nebulized spray pyrolysis. The films deposited on Si are generally polycrystalline, but they are highly oriented on the oxide substrates. The cobaltate films are generally not metallic, but exhibit low resistivity specially when x = 0.3 and 0.5, the latter also exhibiting ferromagnetic characteristics. Films of La_(0.7)Sr_(0.3)CoO_3 show negative magnetoresistance of 35 percent around 180 K. Films of SrRuO_3 are metallic on Si and LaAlO_3 substrates but show an insulator-metal transition on SrTiO_3 around 130 K, around which temperature negative magnetoresistance is observed.