Composition-Dependent Magnetic Anisotropy in Cu/Mn-Based Two-Dimensional Hybrid Perovskite Single Crystals

Abstract

We report the composition-dependent magnetic anisotropy of two-dimensional Ruddlesden-Popper hybrid perovskite single crystals, (C6H5CH2CH2NH3)2CuCl4 (Cu-PEA), (C6H5CH2CH2NH3)2MnCl4 (Mn-PEA), and mixed Cu/Mn compositions. All samples crystallize in a layered structure (Pbca) characteristic of two-dimensional hybrid halide perovskites. X-ray diffraction confirms that the mixed crystals preserve the same structural motif while exhibiting systematic lattice variations with composition. Magnetic measurements reveal distinct ground states for the end members: Cu-PEA shows ferromagnetic ordering with a Curie temperature of 12 K, whereas the Mn-PEA exhibits antiferromagnetic behavior with a Néel temperature of 44 K, while a broader magnetic feature around 80 K reflects short-range magnetic correlations. The mixed Cu/Mn crystals display a composition-dependent evolution of magnetization magnitude and magnetic anisotropy, reflecting the interplay between Cu-based ferromagnetic and Mn-based antiferromagnetic interactions within the layered structure. Curie–Weiss analysis and two-dimensional Heisenberg modeling further indicate direction-dependent exchange interactions, highlighting the intrinsic anisotropic spin coupling of the layered framework. These results demonstrate that compositional mixing provides an effective route to tuning magnetic anisotropy while maintaining the crystallographic structure.