Structural and physical properties of $SrM{n}_{1-x}R{u}_x{O}_3$ perovskites

Abstract

We combine the results of magnetic and transport measurements with neutron diffraction data to construct the structural and magnetic phase diagram of the entire family of SrMn${}_{1-x}$Ru${}_x$O${}_3$ ($0⩽x⩽1$) perovskites. We have found antiferromagnetic ordering of the C type for lightly Ru-substituted materials ($0.06⩽x⩽0.5$) in a similar manner to $R_y$Sr${}_{1-y}$MnO${}_3$ ($R$=La, Pr), due to the generation of Mn${}^{3+}$ in both families of manganite perovskites by either $B$-site substitution of Ru${}^{5+}$ for Mn${}^{4+}$ or $A$-site substitution of $R^{3+}$ for Sr${}^{2+}$. This similarity is driven by the same ratio of $d^4$ / $d^3$ ions in both classes of materials for equivalent substitution level. In both cases, a tetragonal lattice distortion is observed, which for some compositions ($0.06⩽x⩽0.2$) is coupled to a C-type AF transition and results in a first order magnetic and resistive transition. Heavily substituted SrMn${}_{1-x}$Ru${}_x$O${}_3$ materials are ferromagnetic due to dominating exchange interactions between the Ru${}^{4+}$ ions. Intermediate substitution ($0.6⩽x⩽0.7$) leads to a spin-glass behavior instead of a quantum critical point reported previously in single crystals, due to enhanced disorder.

9 pages, 10 figures, accepted for publication in Physical Review B