Stress dependence of ferroelectric and magnetoelectric properties of BiFeO3 thin films on membrane structure

Multiferroic 350-nm-thick BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/ Si(54 mu m) membrane substrates by pulsed laser deposition. To confirm the influence of stress from substrate, ferroelectric and magnetoelectric properties of BiFeO3 thin films have been evaluated with applying stress. For applying stress, we tried to pump out backside of the membrane structure at various pressures. From ferroelectric hysteresis loops, the remanent polarization at the pumping pressure of 0.01 ann increase from 105 to 110 mu C/cm(2), comparing to that without pumping. Under magnetic field of 0.4 T, polarization at zero electric field at pumping pressure of 0.01 atm with maximum applied voltage of 15 V increased from 100 mu C/cm(2) to 103 mu C/cm(2).