Control of periodic ferroelastic domains in ferroelectric Pb1-xSrxTiO3 thin films for nano-scaled memory devices

The scope of this thesis is to study the fundamental properties of ferroelectric and piezoelectric thin films with a view into the future development of new devices. Nowadays piezoelectrics are widely used in sensors such as in airbags and in all kind of electromechanical transducers. They are even used in small, low power, non-volatile memory devices for wireless technology, which keep the information when power is off. Piezo-ferroelectics can also take a role in the very urgent problem of energy consumption. Environmental energy that is overall wasted can be utilized for low-power applications, such as sensors and wifi transmission networks. In particular, mechanical energy of vibrations from different sources can be collected and transformed into electricity by means of piezoelectrics. Car traffic results in deformation of the road pavement and electromechanical transducers built into the highway could recycle part of this energy to feed low power sensors. People commuting on a daily basis in crowded cities also produce sufficient energy to power Light Emitting Diodes (LEDs) or to help recharging your mobile phone on the go. For this prospect to become a reality there is a need for developing efficient piezoelectrics. Non-toxic piezo- and pyro-electric devices may in the future allow developing small low-power implants for inside the human body. They will harvest energy from our own movement or body heat and power devices such as hearing implants or pacemakers that will not need battery replacement. For all these integrated applications, ferroelectrics in thin film form are required.