The role of the Mn, Fe and La dopants on magnetic properties and electronic structures of strontium titanate quinary compounds

Magnetic properties and electronic structures of the quinary compounds (Sr1−yLay)(Ti0.90D0.10)O3 have been calculated using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method, where y represents La concentration (y = 0–0.15) and D indicates the magnetic cations (Mn, Fe). The stability of the magnetic states changes in the opposite manner for the (La, Mn) and (La, Fe) pairs doped into the strontium titanate. The Sr(Ti0.90Fe0.10)O3 (y = 0) shows stable ferromagnetic (FM) state with a high Curie temperature (TC) and a large magnetic moment (MM), whereas the spin glass (SG) state is found for Sr(Ti0.90Mn0.10)O3 (y = 0). A variation of the magnetic properties of (Sr1-yLay)(Ti0.90Fe0.10)O3 (SLTFO) and (Sr1-yLay)(Ti0.90Mn0.10)O3 (SLTMO) is found for different La concentrations. The TC and MM for SLTFO decrease with increasing La concentration. Interestingly, SLTMO compounds exhibit a phase transition from SG to FM states upon introducing La at the Sr site. The density of states (DOS) for La concentrations (y = 0.01, 0.05, 0.10, and 0.15) in SLTFO and SLTMO are calculated to understand the mechanism of the FM stability. The bands shaping and shifting are found in the DOS of SLTFO and SLTMO around the Fermi level. The band manipulations are explained in terms of the orbital hybridization and exchange mechanisms. Keywords: Quinary compounds, KKR-CPA, Curie temperature, Density of states, Strontium titanate, Band shiftin