토토 사이트 순위PHYSICS/BK21 Colloquium[4

[ Multiferroics - Control of Physical Properties by 토토 사이트 Field ]

 * Speaker : Dr. Chan-Ho Yang [Department of Physics, KAIST]

* Place  : Physics Seminar Room (Science Bldg, 3-201)

* Date & Time : Apr, 9 (Fri)  4:00 ~ 5:00 pm

 l  Abstract

The magneto토토 사이트 effect that refers to the inter-coupling phenomena between 토토 사이트 and magnetic degrees of freedom has been extensively studied in the complex-oxide community since large effects were discovered in single compound materials [1, 2]. Especially, bismuth ferrite, BiFeO₃has received a lot of attention due to its multiferroic properties – the coexistence of ferro토토 사이트ity and magnetism – at room temperature. Here we will introduce our concepts to find viable routes to magneto토토 사이트 applications and discuss possible issues from a practical point of view. In addition to the magneto토토 사이트 issues, continuing attention on this compound is expected regarding electronic conduction, photovoltaic effect, and a highly-strained phase of BiFeO₃stabilized by heteroepitaxial growth. Observations of a colossal electro-strain induced by phase competition between two isostructural BiFeO₃phases, i.e, the normal rhombohedral-like phase and the highly-strained tetragonal-like phase, will stimulate more vigorous study of this compound [3]. Finally it will be presented that electronic conduction in doped BiFeO₃films can be modulated by orders of magnitude in an 토토 사이트 way. Using 토토 사이트 fields, we have been able to create, erase, and invert p-n junctions in calcium doped BiFeO₃films [4]. The underlying mechanism will be discussed on the basis of interplay between ionic movement of oxygen vacancies and electronic conduction.

[1] S-W. Cheong and M. Mostovoy, Nature Mater. 6, 13–20 (2007).

[2] R. Ramesh and N. A. Spaldin, Nature Mater. 6, 21–29 (2007).

[3] R. J. Zecheset al., Science 326, 977-980 (2009).

[4] C.-H. Yanget al., Nature Mater.8, 485-493 (2009).

Contact Person : Prof. Yoon Hee JEONG (054-279-2078, yhj@postech.ac.kr )