Ferromagnetic insulating behavior at low temperature induced by Sn doping in the ceramic SrRuO₃

Abstract

Effects of Sn doping at Ru site on the structural, magnetic, and transport behavior of polycrystalline SrRu 1−x Sn x O 3 (x ≤ 0.1) have been investigated here. Substitution of Sn 4+ for Ru 4+ remains the same crystal symmetry with that of Sn-free SrRuO 3 , while induces the Ru(Sn)O 6 octahedral distortions. Samples with the low doping concentration (x ≤ 0.08) show a metallic behavior at high temperature, while a metal to insulator transition occurs at low temperature. On the other hand, an insulator behavior is detected for sample with x = 0.1, which follows Arrhenius-type process in the temperature range of 80-140 K and Mott's variable range hopping model in the temperature range of 140-300 K. Further, we find that Sn 4+ has a significant effect on the magnetic behavior of Sn doping in SrRuO 3 where ferromagnetic transition temperature and magnetic moment decrease rapidly due to octahedral distortion and site dilution.