Site dilution in SrRuO${}_3$: Effects on structural and magnetic properties

Abstract

We have investigated the effect of site dilution with substitution of nonmagnetic element in SrRu${}_{1-x}$Ti${}_x$O${}_3$ ($x$ $\le$ 0.7). The nature of ferromagnetic state in SrRuO${}_3$ is believed to be of itinerant type with transition temperature $T_c$ $\sim$ 162 K. Crystallographically, SrRuO${}_3$ has a distorted orthorhombic structure. Substitution of Ti${}^{+4}$ (3$d^0$) for Ru${}^{+4}$ (4$d^4$), however, does not introduce significant structural modification due to their matching ionic radii. This substitution, on the other hand, is expected to tune the electronic correlation effect and the $d$ electron density in system. With Ti substitution, we find that magnetic moment and Curie temperature decreases but $T_c$ remains unchanged which has been attributed to opposite tuning of electron correlation effect and density of states within framework of itinerant ferromagnetism. The estimated critical exponent ($\beta$) related to magnetization implies a mean-field type of magnetic nature in SrRuO${}_3$. The value of $\beta$ further increases with $x$ which is understood from the dilution effect of magnetic lattice. The system evolves to exhibit Griffiths phase like behavior above $T_c$ which is usually realized in diluted ferromagnet following local moment model of magnetism. Our detail analysis of magnetization data indicates that magnetic state in SrRuO${}_3$ has contribution from both itinerant and local moment model of magnetism.

19 pages, 10 figures

References in corpus (1)

• Quasiparticle Mass Enhancement and Temperature Dependence of the Electronic Structure of Ferromagnetic SrRuO3 Thin Films