Growth and Characterization of Organic Ferroelectric and Magnetic Thin Films
Thesis Defense
12:30 pm –
1:30 pm
Jorgensen Hall Room: 207
Contact:
Physics Department, (402) 472-2770, paoffice@unl.edu
Xuanyuan Jiang
Advisor: Xiaoshan Xu
ABSTRACT: 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 thesis mainly focuses on the growth and characterizations of organic ferroelectric and magnetic thin films. For organic ferroelectrics, I will discuss 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, I focus on a spin crossover (SCO) complex, [Fe{H2B(pz)2}2(bipy)] (BIPY) with two a high spin (HS) and a low spin (LS) states, which can be switched by photoexcitation, pressure, magnetic or electric field. I will mainly explain the interface effect on the spin state transition of BIPY complex. Finally, I will discuss organic multiferroic thin film device fabricated by depositing the ferroelectric CA and SCO BIPY on the interdigital bottom electrodes, especially the isothermal resistive switching.
Advisor: Xiaoshan Xu
ABSTRACT: 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 thesis mainly focuses on the growth and characterizations of organic ferroelectric and magnetic thin films. For organic ferroelectrics, I will discuss 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, I focus on a spin crossover (SCO) complex, [Fe{H2B(pz)2}2(bipy)] (BIPY) with two a high spin (HS) and a low spin (LS) states, which can be switched by photoexcitation, pressure, magnetic or electric field. I will mainly explain the interface effect on the spin state transition of BIPY complex. Finally, I will discuss organic multiferroic thin film device fabricated by depositing the ferroelectric CA and SCO BIPY on the interdigital bottom electrodes, especially the isothermal resistive switching.