Reduction in conduction noise of La–Ca–Mn–O polycrystalline films due to Ag addition

Ag-added ${\mathrm{La}}_{\mathrm{0.67}}{\mathrm{Ca}}_{\mathrm{0.33}}{\mathrm{MnO}}_{\mathrm{3}}\mathrm{(Ag–LCMO)}$ polycrystalline films have been prepared on ${\mathrm{SrTiO}}_{\mathrm{3}}$ substrates by the ultrasonic spray pyrolysis technique and their properties are compared with the ${\mathrm{La}}_{\mathrm{0.67}}{\mathrm{Ca}}_{\mathrm{0.33}}{\mathrm{MnO}}_{\mathrm{3}}\mathrm{(LCMO)}$ films prepared under similar conditions. Addition of Ag in LCMO films improves their surface morphology and reduces their lattice constant. During the synthesis process, Ag in Ag–LCMO film melts and segregates to grain boundaries. In the Ag–LCMO film, normalized voltage noise reduces by more than one order of magnitude, and peak temperature ${\mathrm{(T}}_p)$ and ferromagnetic transition temperature ${\mathrm{(T}}_c)$ increase by 10 and 20 K, respectively. Improvement in surface morphology and better oxygenation of the film due to the presence of Ag leads to reduction in conduction noise of the LCMO film.