Tunable Magnetic Transition Temperatures in Organic-Inorganic Hybrid Cobalt Chloride Hexagonal Perovskites

Magnetically active atomic distances may impact the magnetic ordering in a given system both directly and indirectly. We synthesize three novel quasi-one-dimensional organic-inorganic hybrid cobalt chloride chain compounds (CH₃NH₃CoCl₃, CH(NH₂)₂CoCl₃, and C(NH₂)₃CoCl₃) and characterize their magnetic and thermodynamic properties. These materials crystallize in a hexagonal perovskite-type structure consisting of chains of face-sharing Co-Cl octahedra separated by the respective organic cation. Temperature- and field-dependent magnetic susceptibility analyses reveal that each compound possesses antiferromagnetic intrachain coupling and that the strength of the correlations is comparable across the three materials. Moreover, the interchain Co-Co distance, which depends on the size of the organic cation, is directly related to the temperature at which long-range magnetic ordering occurs.