Mg diffusion in K(Ta0.65Nb0.35)O3 thin films grown on MgO evidenced by Auger electron spectroscopy investigation

The diffusion of Mg in pulsed laser deposited K(Ta0.65Nb0.35)O3 thin films epitaxially grown on (1 0 0) MgO single crystal substrate were investigated by Auger electron spectroscopy (AES). A diffusion of Mg from the substrate into the whole thickness (400 nm) of the as-deposited K(Ta0.65Nb0.35)O3 films was observed with an accumulation of Mg at the surface. Ex situ post-annealing (750 °C/2 h) has led to a homogeneous distribution of Mg in all the ferroelectric coating. This strong reaction between film and substrate promotes a doping effect, responsible for the reduction of K(Ta0.65Nb0.35)O3 dielectric losses in comparison with films grown on other substrates.

► Evidence of long range Mg diffusion from MgO substrate in as deposited KTN films. ► Investigation of Mg diffusion by Auger electron spectroscopy. ► Effect of annealing on homogenization of diffused Mg in KTa0.65Nb0.35O3 films. ► KTa0.65Nb0.35O3 thin films grown by pulsed laser deposition. ► KTa0.65Nb0.35O3 epitaxially grown on MgO.