GROWTH AND CHARACTERIZATION OF ORGANIC FERROELECTRIC AND MAGNETIC THIN FILMS

Compared to inorganic materials, organic materials are environmentally friendly, flexible, and often with low cost. Inspired by these advantages, organic materials-based electronics have been intensively studied for comparable or better functionalities to inorganic electronics. This dissertation mainly focuses on the growth and characterizations of organic ferroelectrics and magnetic thin films. For organic ferroelectrics, we investigate the growth and ferroelectric measurements of thin film croconic acid (CA), a proton-transfer molecular ferroelectric (FE) material with a large spontaneous polarization and a small coercive field, as well as the origin of ferroelectricity in CA in terms of the photostriction effect, including the discovery and explanation of an abnormal long relaxation time. For organic magnetic materials, we focus on a spin crossover (SCO) complex, [Fe{H2B(pz)2}2(bipy)] (BIPY) with high spin (HS) and low spin (LS) states, which can be switched by photoexcitation, pressure, magnetic or electric field. This dissertation mainly explains the interface effect on the spin state transition of BIPY complex. Finally, we fabricate organic multiferroic thin film device by depositing the ferroelectric CA and SCO BIPY on the interdigital bottom electrodes and realize the isothermal resistive switching. Advisor: Xiaoshan X