Ferromagnetism and antiferromagnetism coexistence in Sr1-xLaxRuO3 induced by La-doping

Recently, a spin-glass state appeared experimentally along with suppression of ferromagnetism in polycrystalline La-doped Sr1-xLaxRuO3. Here, we investigated the structural, magnetic and electronic properties of Sr1-xLaxRuO3 (x = 0, 0.125, 0.25, 0.5, 1) based on generalized gradient approximation plus U (GGA + U) by first-principles calculations. The entire series of Sr1-xLaxRuO3 (x = 0, 0.125, 0.25, 0.5, 1) stabilize in the orthorhombic perovskite structure. The spin-polarized calculations give a ferromagnetic half-metal ground state at 0 ≤ x ≤ 0.25, coexistence of a ferromagnetic half-metal state and antiferromagnetic insulating state at x = 0.5 and an antiferromagnetic metal state at x = 1, in good agreement with experimental results. La substitution for Sr decreases RuORu bond angles, resulting in stronger GdFeO3 distortion. The stronger GdFeO3 distortion reduces density of states at the Fermi level, with broadening of Van-hove singularity near the Fermi level. Therefore, suppression of magnetism in Sr1-xLaxRuO3 becomes stronger with increasing x. La-doping weakens a Stoner mechanism for ferromagnetism in SrRuO3. These theoretical results interpret well experiments.