The effect of Mg doping on spin reorientation transition and physical properties of SmFeO3

Present work makes a comparison between the effect of Mg2+ substitution in Sm and Fe-sites [Sm1-xMgxFeO3 and SmFe1-xMgxO3, (x = 0.0, 0.1, 0.2 and 0.3)] on the chemical composition, crystal structure, and magnetic, electrical, and optical properties of SmFeO3 orthoferrite. The analysis of X-ray photoelectron spectroscopy for samples with x = 0.1 indicate Mg doping in Fe-site creates more oxygen vacancy than that of Mg doping in Sm-site. Moreover, there are simultaneously all Fe2+, Fe3+ and Fe4+ oxidation states in these samples. The unit cell volume increase with increasing Mg content in Fe-Site, while the variation of unit cell volume with Mg content are unclear in Sm1-xMgxFeO3 samples. The remnant magnetization in Sm1-xMgxFeO3 samples is approximately one order greater than compared to SmFe1-xMgxO3 ones. The spin reorientation transition of all samples were detected via the temperature dependence of dielectric constant. The spin reorientation temperature was tuned from around 430-470 K for un-doped sample to near room temperature for samples with x = 0.3. A colossal dielectric constant was only observed in samples with Mg doping in the Fe-site. Ferroelectric feature improves in Sm1-xMgxFeO3 samples, while leakage current increases as well. The band gap energy decrease from 2.14 to 1.97 eV via the dilution of the Fe-site with Mg doping.