| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2003: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 2002: ¥3,800,000 (Direct Cost: ¥3,800,000)
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| Research Abstract |
In order to obtain the information about the effect of microscopic dielectric interactions to the macroscopic dielectric properties of dielectric materials, thermal and dielectric properties were investigated of the dipolar-glassy state, which was realized by the frustration effect between ferroelectricity and antiferroelectricity in the solid-solution systems of ferroelectric and antiferroelectric materials. Further, the structures and dielectric properties of thin films of BaTiO_3, which is a typical ferroelectric material, and of SrTiO_3, which shows a quantum paraelectric property, formed on quartz glass substrate by RF sputtering method were studied to elucidate the correlation between the size of dielectric interaction region and the macroscopic dielectric properties. The results are as follows :
1.The dipolar-glass transition in the solid-solution system of PyH(BF_4)_<1-x>(PF_6)_x (Py = C_5NH_5) was detected successfully by an adiabatic calorimetry as a glass transition. This is the first case where the dipolar-glass transition was observed calorimetrically, and the result strongly suggests that the dipolar-glassy state is, in essence, a frozen-in non-equilibrium state of the configuration of dipoles due to slowing down of the reorientation rate with decreasing temperature.
2.The grain sizes of crystallites formed in the thin films of BaTiO_3 and SrTiO_3 were found to be controlled up to 30 and 40 nm for BaTiO_3 and SrTiO_3, respectively, by changing the temperature of the quartz glass substrate during the film formation by the sputtering method. The crystallites of BaTiO_3 with the nm-grain size showed the crystal structure belonging to cubic crystal system differently from the bulk, and the dielectric permittivity of the film samples was observed to become larger with the increase of the grain size in the temperature range between 200 and 300 K.
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