Unveiling Photoluminescence Signatures of Magneto‐Optical Coupling in Layered Hybrid Manganese Chloride Perovskites

Abstract Understanding the interplay between magnetic ordering and light emission is crucial for developing magneto‐optical technologies. However, this phenomenon is poorly understood since observations of this coupling vary significantly across materials. In this context, hybrid organic‐inorganic metal halide perovskites (HOIPs) that incorporate Mn 2+ ions are a chemically and structurally tunable platform for exploring this phenomenon, since they exhibit magnetic ordering and photoluminescence (PL) emission. Here, two antiferromagnetic Mn‐based HOIPs with different organic cations are studied, resulting in distinct lattice stiffness, Mn 2+ ‐Mn 2+ distance, and octahedral distortion. Temperature‐dependent PL excitation spectroscopy reveals changes in crystal field splitting energy and Racah parameters well above the Néel temperature (T N ), indicating the emergence of Mn 2+ ‐Mn 2+ magnetic interactions prior to reach long‐range magnetic ordering. These variations align with the observed changes in temperature‐PL evolution. The compound with a more rigid lattice shows stronger changes closer to T N , suggesting combined effects of magnetic polarons and spin‐canting. In contrast, magnetic modifications induced by magnetic polarons prevail in the HOIP with a softer lattice. These results reveal the complexity of the magneto‐optical coupling in Mn‐based HOIPs and provide new insights into this field extensible to other 2D materials that exhibit this phenomenon with potential for advanced magneto‐optical applications.