Ferroelectricity and negative temperature coefficient of resistance in pulsed-laser-deposited (Pb,Sr)TiO3 films

(Pb,Sr)TiO3 films deposited on Pt/SiO2/Si substrates by pulsed-laser deposition (PLD) at 400 deg C with oxygen pressures ranging from 50 to 200 mTorr have been investigated. The paraelectricity-to-ferroelectricity transition of films depends on the oxygen pressure during deposition. Films deposited at 200 mTorr exhibit paraelectric-like nature, whereas films deposited at lower pressures present the ferroelectric characteristic. The (Pb,Sr)TiO3 film is found to exhibit a negative temperature coefficient of resistance (NTCR) at the measurement temperature ranging from 30 to 390 deg C. This work demonstrates that the ferroelectricity/paraelectricity and the temperature coefficient of resistance of (Pb,Sr)TiO3 films could be controlled by oxygen pressures during PLD.