Magnetic behavior of the 5d1 Re-based double perovskite Sr2ZnReO6

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 (5d1) ordered double perovskite oxide Sr2ZnReO6 combining synchrotron x-ray diffraction (XRD), magnetic susceptibility, muon spin relaxation (& micro;SR) measurements, and density functional theory (DFT) calculations. XRD reveals that Sr2ZnReO6 crystallizes in the monoclinic structure (space group P21/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 & micro;SR measurements detect static and spatially disordered internal fields below TM 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 & micro;B) and very small static moment (<= 0.2 & micro;B) derived from & micro;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 Sr2ZnReO6, 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 5d1 double perovskites.