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in the relaxor ferroelectrics (1-x)Pb(Zn
Nb
)O
-xPbTiO (
= 0.09) studied by X-ray diffuse scattering and coherent X-ray scatteringOwada, Kenji; Mizuki, Junichiro*; Matsushita, Mitsuyoshi*; Namikawa, Kazumichi*
Physical Review B, 90(10), p.104109_1 - 104109_12, 2014/09
Times Cited Count：6 Percentile：29.37(Materials Science, Multidisciplinary)The paraelectric (PE) to ferroelectric (FE) first-order phase transition of 0.91Pb(ZnNb)O-0.09PbTiO (
= 455 K on cooling) has been studied by the complementary use of X-ray diffuse scattering (XDS) and coherent X-ray scattering (CXS). XDS was mainly used to investigate the FE regions, while CXS was mainly used to investigate the PE regions above on cooling. The diffuse scattering intensity due to the appearance of FE regions shows a maximum at 
K. The diffuse scattering is dynamic in nature and the softening trend changes to a hardening trend at 
. This means that the FE instability is maximum at and therefore the FE regions are well stabilized below 
. The spatial autocorrelation function obtained by CXS, corresponding to the texture of PE regions, starts to rapidly change at about and is most unstable at . We conclude that a heterophase fluctuation occurs between and near the phase transition. The heterophase fluctuation can be expected to correlate to the low-frequency dielectric dispersion and contribute to the phase transition as a precursor phenomenon of the first-order phase transition.
Owada, Kenji; Shimomura, Susumu*; Nakao, Hironori*; Matsushita, Mitsuyoshi*; Namikawa, Kazumichi*; Mizuki, Junichiro
Journal of Physics; Conference Series, 320, p.012086_1 - 012086_5, 2011/09
Times Cited Count：0 Percentile：0.03We have performed an X-ray photon correlation spectroscopy measurement of 91
Pb(ZnNb)O-9PbTiO and found a slow structural fluctuation in time near 
. The slow fluctuation consists of long-term and short-term fluctuations. We have derived the short-term fluctuation from the intensity fluctuations and found out the relaxation time to be an order of 10s. It is suggested that the slow fluctuation is owing to the competition between macroscopic tetragonal symmetry and the microscopic orthorhombic symmetry. The competition should be a main reason for the low-frequency dielectric permittivity.
in Pb(ZnNb)O-9%PbTiOPbTiOOwada, Kenji; Mizuki, Junichiro; Namikawa, Kazumichi*; Matsushita, Mitsuyoshi*; Shimomura, Susumu*; Nakao, Hironori*; Hirota, Kazuma*
Physical Review B, 83(22), p.224115_1 - 224115_7, 2011/06
Times Cited Count：8 Percentile：37.08(Materials Science, Multidisciplinary)Complementary use of coherent X-ray diffraction (CXD), X-ray diffuse scattering, conventional X-ray diffraction techniques and dielectric measurements has enabled us to investigate Pb(ZnNb)O-9%PbTiO with a multiple-length-scale approach from the macroscale (lattice constants, bulk averaged) and microscale to the nanoscale (polar nanoregions (PNRs)) and discuss the contribution of each scale to the dielectric permittivity.
Owada, Kenji; Namikawa, Kazumichi*; Shimomura, Susumu*; Nakao, Hironori*; Mimura, Hidekazu*; Yamauchi, Kazuto*; Matsushita, Mitsuyoshi*; Mizuki, Junichiro
Japanese Journal of Applied Physics, 49(2), p.020216_1 - 020216_3, 2010/02
Times Cited Count：3 Percentile：15.44(Physics, Applied)Owada, Kenji; Namikawa, Kazumichi; Mizuki, Junichiro; Shimomura, Susumu*; Nakao, Hironori*; Ito, Kazuki*; Matsushita, Mitsuyoshi*; Yoneda, Yasuhiro; Murakami, Yoichi*; Hirota, Kazuma*
Transactions of the Materials Research Society of Japan, 32(1), p.7 - 10, 2007/03
An X-ray speckle pattern well reflects a particle or domain alignment on the inside of materials. Detecting the alignment is important for understanding a function of the materials such as ferroelectric, piezoelectric materials, photonic crystals and so on. We have thus constructed the apparatus for coherent X-ray diffraction at BL22XU@SPring-8, high quality slits for obtaining the full coherent X-ray beam, high resolution X-ray CCD camera for obtaining the well-resolved speckle pattern, and so on. By using the devices, we have successfully observed the speckle pattern from CuAu, the ferroelectric material PZN-9%PT (91%Pb(ZnNb)O-9%PbTiO) and Sr-doped BaTiO. The 2DFFT image gives us a spatial autocorrelation function which includes the information of the arrangement of the domains in the crystal within micrometers scale.
Owada, Kenji; Namikawa, Kazumichi; Mizuki, Junichiro; Matsushita, Mitsuyoshi*; Shimomura, Susumu*; Nakao, Hironori*; Hirota, Kazuma*
no journal, ,
no abstracts in English
Owada, Kenji; Mizuki, Junichiro; Namikawa, Kazumichi*; Matsushita, Mitsuyoshi*; Shimomura, Susumu*; Nakao, Hironori*; Hirota, Kazuma*
no journal, ,
Ishino, Masahiko; Namikawa, Kazumichi; Matsushita, Mitsuyoshi*; Owada, Kenji; Shimizu, Daisuke*; Sakamoto, Junya*; Mizuki, Junichiro
no journal, ,
no abstracts in English
Owada, Kenji; Namikawa, Kazumichi*; Matsushita, Mitsuyoshi*; Mizuki, Junichiro*
no journal, ,
no abstracts in English
Owada, Kenji; Namikawa, Kazumichi*; Matsushita, Mitsuyoshi*; Mizuki, Junichiro*
no journal, ,
It is generally known that the temperature dependence of the dielectric constants of relaxor ferroelectrics near morphotropic phase boundary (MPB) shows a cooling-rate dependence. This is due to a domain fluctuation across a tetragonal-to-rhombohedral phase transition. In this paper, we focus on the tetragonal-to-rhombohedral phase transition (T
300 K) in relaxor ferroelectrics PZN-9%PT, which is very close to MPB. We have simultaneously measured the frequency-dependent dielectric constants and the coherent X-ray scattering directly reflecting a domain configuration. The results directly show an effect of the domain fluctuation on a low-frequency dielectric permittivity. These results should strongly relates to the cooling-rate dependence on the temperature dependence of the dielectric constants.
