Doping Effects on Magnetic Layered Hybrid Organic–Inorganic Transition Metal Halide Perovskites

The modulation of the magnetic properties of hybrid organic-inorganic perovskites (HOIPs) is key for their implementation in spintronics. The introduction of different transition metal cations at the octahedral sites can further enhance their structural and chemical versatility. Here, we report three different doped systems, (PEA)₂M¹_1-<i>x</i>M²_<i>x</i>Cl₄ (M = Cu²⁺, Mn²⁺, Co²⁺; PEA = phenethylammonium), to highlight how the presence of two metal cations with different spin configurations can modify their structural, optical, and magnetic properties. For low dopant content (<i>x</i> < 0.1), we obtain layered single crystalline phases confirmed by X-ray diffraction and Raman spectroscopy. In (PEA)₂Mn_1-<i>x</i>Co_<i>x</i>Cl₄ compounds, we observe antiferromagnetic behavior with a Neel temperature that varies with the dopant content and the disappearance of spin-flopping and spin-canting behavior due to the incorporation of Co²⁺ ions in the HOIP lattice. By contrast, the single-phase (PEA)₂Mn_1-<i>x</i>Cu_<i>x</i>Cl₄ crystal shows a canted antiferromagnetic behavior, typical of Mn²⁺ HOIPs, and the single-phase (PEA)₂Cu_1-<i>x</i>Co_<i>x</i>Cl₄ compound behaves as a 2D ferromagnet with properties almost independent of the Co²⁺ dopant content. Our work demonstrates that, with the proper choice of dopant and host, the magnetic properties of layered HOIPs can be modified using low dopant concentrations, providing a powerful approach to create tailored 2D magnets.