Evidence of ferroelectric behaviour in CaCu3Ti4O12 thin films deposited by RF-sputtering

• Main Authors: Cesar R. Foschini, Bruno Hangai, Pedro Paulo Ortega, Elson Longo, Mário Cilense, Alexandre Z. Simões
• Format: Article
• Language: English
• Published: University of Novi Sad 2019-09-01
• Series: Processing and Application of Ceramics
• Subjects: calcium copper titanate; CCTO; ferroelectricity; RF-sputtering; thin films
• Online Access: http://www.tf.uns.ac.rs/publikacije/PAC/pdf/PAC%2045%2001.pdf
• ISSN: 1820-6131; 2406-1034

The origin of abnormal ferroelectric and unusual piezoelectricity in the polycrystalline CaCu3Ti4O12 (CCTO) thin films deposited by RF-sputtering on Pt/Ti/SiO2/Si (100) substrates was explored. The CCTO thin films, deposited at room temperature followed by annealing at 600 °C for 2 h in a conventional furnace, have a cubic structure with lattice parameter a = 7.379 ± 0.001 Å and without any secondary phases. No polarization loss up to 1010 switching cycles, with a switched polarization ∆P of 30 µC/cm2 measured at 400 kV/cm was evidenced. The piezoelectric coefficient investigated by piezoresponse force microscopy (PFM) was approximately 9.0 pm/V. This may be the very first example of exploring the origin of ferroelectric behaviour for a material that possesses space charge polarization with highly resistive grain boundaries in the polycrystalline state.