Notes on the dynamic behavior of hysteretic devices

A large class of sensors has nonlinear input-output characteristics; the task of addressing their dynamic behavior is very interesting. These sensors include magnetic field sensors (fluxgate sensors), SQUID devices, ferroelectric sensors, and mechanical sensors made of piezoelectric materials. Over the past few years there has been increasing interest in the sensing properties of ferroelectric devices based on piezoelectric, dielectric, and conduction phenomena. The principal types of sensors are infrared sensors, pressure sensors, force and motion sensors, flow sensors, hydrophones, ultrasonic transducers for medical imaging, and material testing and temperature sensors. Several application fields are automotive, aerospace, communications, and environmental monitoring. Nonvolatile random access memories are another field of application. A conceptual understanding of switching dynamics for these devices is of scientific and technological interest and requires experiments to observe their static and dynamic behavior and to develop suitable models. In the field of measurement devices, for example, the design of sensors and actuators requires the use of efficient models. This emphasizes the need for both models and user friendly experimental setup allowing for the characterization of such classes of devices. Following sections describe the behavior of a ferroelectric device and an innovative analytical model aimed to predict its dynamics.