Experimental and Theoretical Evidence of Weak Spin–Lattice Coupling in the Double Perovskite Sr₂YRuO₆

Sr₂YRuO₆ is a material that provides an ideal platform for studying magnetic frustration in three-dimensional geometries. Herein, we combine Raman spectroscopy and density functional theory calculations to establish connections between the lattice dynamics and magnetic states in Sr₂YRuO₆ single crystals. The x-ray diffraction profiles reveal that Sr₂YRuO₆ possesses an ordered double-perovskite structure with distorted monoclinic symmetry. Three magnetic phase transitions are observed and linked to the presence of weak ferromagnetism at 135 K and short- and long-range antiferromagnetic orderings at 32 and 26 K. The oxygen-octahedron antistretching and stretching modes, observed at 570 and 766 cm⁻¹, exhibit anomalies near the magnetic phase transition temperatures, indicating an intriguing interplay between the lattice and spin degrees of freedom. Their spin–phonon coupling constants of 0.7 cm⁻¹ reflect the weak spin–lattice interactions in Sr₂YRuO₆.