Magnetic behavior of the 5 d 1 Re-based double perovskite Sr 2 ZnReO 6

The subtle interplay between spin-orbit coupling, exchange interactions, and cation ordering can lead to exotic magnetic states in transition-metal ions. We report a comprehensive study of the Re-based ( 5 d 1 ) ordered double perovskite oxide Sr 2 ZnReO 6 combining synchrotron x-ray diffraction (XRD), magnetic susceptibility, muon spin relaxation ( μ SR ) measurements, and density functional theory (DFT) calculations. XRD reveals that Sr 2 ZnReO 6 crystallizes in the monoclinic structure (space group P 2 1 / n ) at low temperature. Magnetic susceptibility data indicate a transition below ∼ 13 K , with M – H loops showing ferromagnetic-like hysteresis and an unusually high coercive field of 23 kOe at 2 K. Zero-field μ SR measurements detect static and spatially disordered internal fields below T M ≃ 12 K, consistent with a canted antiferromagnetic ground state determined by detailed DFT and force-theorem in Hubbard-I calculations. The reduced high-temperature effective moment ( ∼ 0.76 µ B ) and very small static moment ( ≲ 0.2 µ B ) derived from μ SR analysis and local-field simulations indicate a decisive role of spin-orbit coupling. Through a combined experimental and computational approach we unambiguously determine the canted antiferromagnetic order in Sr 2 ZnReO 6 , showing that a very small ordered moment coexists with an exceptionally large coercivity. These results underscore the crucial role of spin-orbit coupling and orbital ordering, providing new insights into magnetism in 5 d 1 double perovskites.