Structural, electronic and magnetic properties of Fe-doped strontium ruthenates

By employing a combined approach of density-functional theory (DFT) and dynamical mean-field theory (DMFT) calculations, we examine the structural, electronic, and magnetic characteristics of two distinct strontium ruthenates: Sr 2 RuO 4 , an unconventional superconductor, and the correlated metal SrRuO 3 , both at 50% Fe-doping level. In both Sr 2 Fe 0.5 Ru 0.5 O 4 and SrFe 0.5 Ru 0.5 O 3 , the original ruthenium (Ru) and the dopant iron (Fe) atoms adopt 3-dimensional and 2-dimensional G-type structures, respectively. The hybridization between Fe-3d and Ru-4d is comparatively weaker than in other double perovskite systems. The interplay between strong correlations and reduced itinerancy results in significant spin splitting at Fe and Ru sites. Consequently, a charge transfer process, along with the super-exchange effect, leads to antiferromagnetically coupled Fe 3+ and Ru 5+ ions and establishes a semiconducting ferrimagnetic order. Subsequent DMFT calculations demonstrate the persistence of the ferrimagnetic order even at room temperature (300 K). These findings align with prior reports on SrFe 0.5 Ru 0.5 O 3 , thus reinforcing the notion that 3d–4d transition metal oxides hold considerable promise as candidates for high-performance spintronic devices, such as spin-valve sensors and spintronic giant magnetoresistance devices.