Cationic disorder effect on the structural and magnetic properties in SmCr1−xFexTiO5

Abstract

Combining synchrotron X-ray and neutron powder diffraction with Mössbauer and Raman spectroscopy and magnetization measurements, a comprehensive experimental study of the SmCr_1−xFe_xTiO₅ series (x = 0, 0.25, 0.50, 0.75 and 1) is presented. The compounds which exhibit a structure derived from mullite crystallize in the orthorhombic Pbam space group in the entire series, and from room temperature down to 2 K. The transition metals occupy two crystallographic sites, one octahedron (M_octO₆) and one square-based pyramid (M_pyrO₅), in a non-random fashion depending on x. Accordingly, different magnetic behaviours are generated from long range antiferromagnetism to spin glass. This study demonstrates that the impact of the Fe for Cr substitution on the magnetic properties is mainly due to the distribution of Ti⁴⁺ (d⁰), Cr³⁺ (d³) and Fe³⁺ (d⁵) over the M-cationic framework rather than the induced structural effect.