저널

Epitaxial (La, Sr)$CoO_3/Pb(Zr,;Ti)O_3/(La,;Sr)CoO_3$by pulsed laser deposition for ferroelectric field effect transistor. Epitaxial $LaCoO_3/Pb(Zr,;Ti)O_3/(La,;Sr)CoO_3$ heterostructures exhibited 70$mu C/cm^2$ and 17 $mu C/cm^2$at a positively and negatively poled states, respectively. On the other hand, epitaxial (La, Sr)$CoO_3/Pb(Zr,;Ti)O_3/LaCoO_3$heterostructures show the remnant polarization states opposite to the $LaCoO_3/Pb(Zr,;Ti)O_3/(La,;Sr)CoO_3$ heterostructures. This indicates that the interface between (La, Sr)$CoO_3$ (LSCO) and $Pb(Zr, Ti)O_3(PZT)$ layers affects the asymmetric polarization remanence through electrochemical nature. The resistivity of $LaCoO_3$ (LCO) layer was found to be dependent on an ambient oxygen, primarily the ambient oxygen pressure during deposition. The resistivity of the LCO layer varied in the range of 0.1-100 $Omega$cm. It is suggested that, with an appropriate resistivity of the LCO layer, the LCO/PZT/LSCO heterostructure can be used as the ferroelectric field effect transistor.