Microstructure and electrical properties of Ln2Ti2O7 (Ln=La, Nd)

The effects of microstructure on the electrical properties of Ln2Ti2O7 (Ln=La, Nd) films were investigated by depositing on Pt/Ti/Si and Y2O3/Si substrates using the sol-gel and spin-coating method. The films were crystallized at 800 deg. C in O2 for 30 min in a tube furnace by direct insertion. According to the A-site cation, the different tendencies in ferroelectric properties between films and single crystals were observed. The ferroelectric parameters are: Pr=4.4 μC/cm2, Ec=131 kV/cm for Nd2Ti2O7 film; and Pr=1.8 μC/cm2, Ec=75.28 kV/cm for La2Ti2O7 film, respectively. C-V characteristics of Ln2Ti2O7/Y2O3/Si structure were measured to investigate the ferroelectric memory effects at 1 MHz with a bias sweep rate of 0.18 V/s. The values of the memory window were 2.7 and 2.3 V for Nd2Ti2O7 and La2Ti2O7 films with 7 V of applied voltage, respectively