Piezoelectric, ferroelectric properties of multiferroic YMnO3 epitaxial film studied by piezoresponse force microscopy

• YMnO3 thin film with (0 0 0 l) orientation was grown on Al2O3 substrate by pulsed laser deposition.
• Piezoelectric and ferroelectric properties of the YMnO3 thin film investigated by piezoresponse force microscopy were reported for the first time.
• Typical butterfly-shape amplitude loop and a hysteresis phase loop were observed.

Using piezoresponse force microscopy (PFM), we mainly studied the piezoelectric, ferroelectric properties of YMnO3 thin film deposited on ZnO:Al/Al2O3 substrate by pulsed laser deposition. X-ray diffraction measurement indicated that YMnO3 film and ZnO:Al bottom electrode exhibit (0 0 0 l) preferred orientation. The leakage currents of the YMnO3 film are related with temperature. The resistivity of the film at 40 kV/cm is about 2.3×107 Ω cm at room temperature (300 K). Piezoresponse force microscopy images and local piezoresponse loops reveal the piezoelectric and ferroelectric properties of the YMnO3 film at room temperature. Polarizations (P) versus electric field (E) measurements further testify the ferroelectricity of the YMnO3 film.