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The A-site rare earth-doped Bi₄Ti₃O${}_{12}$ (BTO) has been highly interested in nonvolatile ferroelectric random memory devices, piezoelectric devices, electro-optical devices, capacitors, sensors, transducers, etc., due to its low coercive field and superior fatigue resistance properties. However, single B-site doping has not received corresponding attention. In this work, BTO and Bi₄Ti${}_{3.9}$Sn${}_{0.1}$O${}_{12}$ (BTS) thin films were prepared by sol–gel method, in which the doping of Sn effectively restrained the grain growth and decreased the grain size, as well as diminished the formation of oxygen vacancies and enhanced the breakdown field. This leads to a significant enhancement of the ferroelectric properties of the BTO films. The final BTS films exhibit excellent saturation P–E loops with a remnant polarization (2$P_r$) of 94.4$\mu$C/cm² and a coercive field (2$E_c$) of 0.69MV/cm at a maximum electric field of 2.8MV/cm. The ferroelectric fatigue and dielectric properties of BTS film were also characterized. The results suggest that doping of Sn at B-site can effectively improve the breakdown strength and enhance the ferroelectric properties of the BTO film.

The crystal structure and magnetic properties of (Ru_1-xSn_x)Sr₂EuCeCu₂O_z and Ru(Sr_2-xLa_x)EuCeCu₂O_z(0≤x≤0.1) samples have been investigated to shed light on the doping-induced changes in the magnetic properties of Ru-1222 system. We show that La substitution for Sr leads to an increase in the temperature where the ferromagnetic component is observed and a moderate suppression of the ferromagnetic component whereas Sn substitution for Ru results in a significant decrease of the volume fraction of the ferromagnetic phase as well as a decrease in the magnetic ordering temperature. The experimental results are discussed in connection with the structural data studied by Rietveld refinement of the x-ray diffraction data.