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The ceramic composites of Sm 1- x Bi x CrO 3 (x = 0, 0.1, 0.2, 0.3) have been prepared by solid state reaction. X-ray diffraction patterns demonstrate that Bi-doped polycrystalline samples match with standard pattern of SmCrO 3. After Bi doping, the lattice constants in three directions increase slightly. The thermal expansion properties were studied by X-ray powder diffraction over the temperature range from 100 to 400 K. The results showed that the compound SmCrO 3 exhibits positive thermal expansion behavior in the a and c directions in the whole measurement temperature range. The anomaly is that in the b direction the lattice exhibits positive thermal expansion behavior at low temperatures, while above 200 K it exhibits near zero thermal expansion behavior. The thermal expansion behaviors of all Bi-doped SmCrO 3 are similar to that of SmCrO 3 , but unexpectedly, negative thermal expansion behaviors were observed in the b direction above 200 K in the highly Bi doped samples. The dielectric measurement shows that there are two thermal activation processes in all Sm 1- x Bi x CrO 3 (x = 0, 0.1, 0.2, 0.3) respectively, with the low-temperature activation corresponding to the grain itself, while the high-temperature activation comes from the grain boundary. After low-temperature thermal activation, with increasing temperature, the enhanced vibration of the corner oxygen atoms of the CrO 6 octahedron is mainly perpendicular to the b axis, which leads to the near zero thermal expansion behavior in the b direction. Moreover, after high-temperature thermal activation, as the temperature increases, the enhanced interaction between Bi3+ and the free oxygen atom (space oxygen atom) at the grain boundary will further lead to the negative thermal expansion behavior in the b-direction of the high concentration doped samples. [ABSTRACT FROM AUTHOR]

With the trend of electronic information technology towards miniaturization, integration and intelligence, higher requirements are put forward for the performance of dielectric ceramic materials. In this paper, a series of doped samples Sm 2 O 3 -xZnO (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8) were successfully prepared by the traditional solid state reaction method, and the complex dielectric properties of the ceramic samples were investigated as a function of temperature (100 K–400 K) and frequency (102–106 Hz) separately. A new phase Zn 6.76 Sm 2.58 O 10.6 was found in all samples, and all samples were complex. At a higher temperature, 350 K, with the increase of ZnO doping content, the maximum dielectric constant is 434.7, the dielectric loss is as low as 0.0098, and the dielectric performance is significantly increased compared with room temperature. UV–Vis DRS test showed that the absorbance of the sample increased with the increase of ZnO content, and the side reaction showed that the dielectric constant and dielectric loss of the sample were improved under the action of UV light. These provide an experimental basis for the application of samarium based dielectric ceramics. [ABSTRACT FROM AUTHOR]