Advanced Functional Oxide Materials
소속 :
연사 : Prof. Manfred Martin (Germany, Aachen University)
일시 : 2012-04-05 17:00 ~
장소 : 500동 목암홀
일 시 : 2012년 4월 5일 오후 5시
장 소 : 500동 목암홀
-Abstract-
Ionic and electronic transport in functional oxide materials is of great relevance for applications in the fields of energy and data storage, e.g. solid oxide fuel cells (oxygen ion conductivity), oxygen per¬meation membranes (ambipolar diffusion of oxygen), or data storage materials (electronic and/or ionic conductivity). In this contribution our recent work on the influence of defect inter-actions, grain structure and space charge effects, and electronic structure will be discussed for highly non-stoichiometric crystalline and amorphous oxides.
The general phenomenon of a maximum in the oxygen ion conductivity against dopant fraction will be analyzed in terms of defect interactions and using density functional theory and kinetic Monte Carlo simulations. In nano-crystalline oxide ion conductors, space charge effects at grain boundaries and surfaces hinder oxygen ion transport .
Highly non-stoichiometric oxides exhibit fascinating electronic properties. An example is the complex perovskite oxide (Ba,Sr)(Co,Fe)O3-δ in which not only the transition metal ions cobalt and iron but also oxygen ions act as redox centers, as revealed by comparing thermogravimetric data and spectroscopic information from X-ray absorption spectroscopy .
In amorphous oxides internal disproportionation reactions can induce an insulator-metal transition and may have an immediate impact on applications such as electronic devices and permanent data storage. This novel mechanism and its implications will be discussed considering experimental and theoretical results for amorphous and highly non-stoichiometric gallium oxide.
장 소 : 500동 목암홀
-Abstract-
Ionic and electronic transport in functional oxide materials is of great relevance for applications in the fields of energy and data storage, e.g. solid oxide fuel cells (oxygen ion conductivity), oxygen per¬meation membranes (ambipolar diffusion of oxygen), or data storage materials (electronic and/or ionic conductivity). In this contribution our recent work on the influence of defect inter-actions, grain structure and space charge effects, and electronic structure will be discussed for highly non-stoichiometric crystalline and amorphous oxides.
The general phenomenon of a maximum in the oxygen ion conductivity against dopant fraction will be analyzed in terms of defect interactions and using density functional theory and kinetic Monte Carlo simulations. In nano-crystalline oxide ion conductors, space charge effects at grain boundaries and surfaces hinder oxygen ion transport .
Highly non-stoichiometric oxides exhibit fascinating electronic properties. An example is the complex perovskite oxide (Ba,Sr)(Co,Fe)O3-δ in which not only the transition metal ions cobalt and iron but also oxygen ions act as redox centers, as revealed by comparing thermogravimetric data and spectroscopic information from X-ray absorption spectroscopy .
In amorphous oxides internal disproportionation reactions can induce an insulator-metal transition and may have an immediate impact on applications such as electronic devices and permanent data storage. This novel mechanism and its implications will be discussed considering experimental and theoretical results for amorphous and highly non-stoichiometric gallium oxide.
