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Matsuo, Yoji*; Hoshiyama, Takuya*; Mori, Shigeo*; Yoshii, Kenji; Michiue, Yuichi*; Kambe, Takashi*; Ikeda, Naoshi*; Brown, F.*; Kimizuka, Noboru*
Japanese Journal of Applied Physics, 48(9), p.09KB04_1 - 09KB04_3, 2009/10
Times Cited Count:1 Percentile:5.01(Physics, Applied)We have investigated an average crystal structure and microstructures in LuFe
Ti
O
by the transmission electron microscopy (TEM), in combination with the dielectric measurements. In this work, high-qualitypolycrystalline samples of LuFe
Ti
O
were successfully synthesized in air by the conventional solid state reaction. The average crystal structure at room temperature is characterized by the hexagonal structure (space group:
6
cm). Dielectric measurements revealed that LuFe
Ti
O
shows broad dielectric dispersion around 570 K, which should originate from the formation of the polar domain structures on the nanometer scale.
O
(R=rare earths)Yoshii, Kenji; Yoneda, Yasuhiro; Ikeda, Naoshi*; Matsuo, Yoji*; Hoshiyama, Takuya*; Horibe, Yoichi*; Mori, Shigeo*
no journal, ,
We have investigated the Fe-site substitution effects in the electronic ferroelectric RFe
O
(R=rare earths). It was found that continuous solid solutions were formed for the Mn substitution; RFe
Mn
O
was synthesized for 0
x
1. On the other hand, the substitution of other cations (such as Cu and Ga) was possible in limited x regions; e.g., Ga could be substituted for 0
x
0.4-0.5 It was also found that the low-temperature magnetization and the dielectric constant were reduced by the substitution. Considering the mechanism of dielectric response in RFe
O
, the change of the physical properties likely arises from a change of electron transfer between the Fe-site ions.
Ti
O
(R=Lu,Yb)Hoshiyama, Takuya*; Mori, Shigeo*; Matsuo, Yoji*; Funae, Takeshi*; Kambe, Takashi*; Ikeda, Naoshi*; Kimizuka, Noboru*; Yoshii, Kenji; Michiue, Yuichi*
no journal, ,
We have investigated the crystal structure and physical properties of RFe
Ti
O
(R=Lu,Yb). The samples were prepared by the solid-state reaction method in air. X-ray and electron diffraction measurements showed that the materials have the same crystal structure as that of multiferroic RMnO
. Magnetic measurements showed the absence of magnetic transition below 400 K. Dielectric measurements showed the peak of dielectric constant above room temperature, suggesting a existence of ferroelectric phase transition at high temperatures.
Mn
O
, 2Matsumoto, Keisuke*; Hoshiyama, Takuya*; Oishi, Daisuke*; Akahama, Hiroshi*; Yoshii, Kenji; Kano, Jun*; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Mori, Shigeo*
no journal, ,
We have investigated the physical properties of YbFe
Mn
O
, a derivative system of the electronic ferroelectric RFe
O
(R: rare earths). Electron diffraction measurements showed taht long-range charge ordering of the Fe-3d charges was observed at room temperature for x=0; this ordering is the origin of ferroelectricity. The x=0.1 oxide showed diffuse scattering patterns at room temperature, instead of the charge-ordered pattern. Thus, 5% Mn substitution can collapse the long-range charge ordering. We will also present the correlation between the magnetic/dielectric properties and the crystal structure.