Observation of ferroelectric nanostructure by X-ray laser speckle technique

Polarization domain has long been recognized and interested from early days of ferroelectrics research from application and fundamental point of view. Meanwhile the behavior of the response of nanostructure among the polarization domain at near the phase transition temperature under an external electric field is the vital for the understanding of the high performance of the ferroelectrics. Observation of the polarization domain has been performed by polarization microscope, atomic force microscope, electron microscope, and so on. All these observations by microscopes are static one. Unfortunately, however, it is of no use for the dynamic observation. X-ray photon correlation spectroscopy (XPCS) by synchrotron radiation (SR) is applied to the observation of relaxation phenomena of the nanostructure in matters. Due to the low coherent flux of SR, 0.1% order of total flux, it is difficult to apply the SR XPCS to the fast phenomena with relaxation time faster than 100 musec or so. On the other hands, plasma based soft X-ray laser (SXRL) however 1 second accumulation of SR X-ray photons are contained within its one pulse ,7 psec, coherent flux is over the 90% even with low repetition rate, 0.1 Hz. This is the report of our observation of nanostructure of ferroelectrics by use of SXRL.