Neutron Diffraction Study on the Magnetic Structure of the Promised Multiferroic Hybrid Perovskite [C(ND2)3]Cu(DCOO)3 and Its Centrosymmetric Analogues

Abstract

This report presents with one of the rare experimental studies on the magnetic structure of hybrid framework materials, [C(ND2)3]Me2+(DCOO)3 (Me = Cu, Mn, and Co), by using neutron powder diffraction. Copper guanidinium formate (CuGF) having a polar structure is a promised multiferroic member of the hybrid perovskite metal guanidinium formates and its Mn/Co analogues possessing a centrosymmetric structure. Previous investigations based on ab initio calculations have suggested that CuGF is a multiferroic whose magnetic space groups are assignable either to Pn′a′21 or Pna′21′. Our neutron experiments concurrently reject the Pna′21′ possibility and suggest the magnetic structure of CuGF as either Pna21 or Pn′a′21, with both exhibiting “Type-A” magnetic ordering, free from ferromagnetic ordering along the polar-axis, with spins lying in the ab plane. In contrast to CuGF, its centrosymmetric analogues Mn/CoGF are found to display “Type-G” magnetic ordering, with their spins aligned along the b and c axis, respectively. The in-depth evaluation of magnetic structure of the metal guanidinium formate frameworks could be helpful in the understanding and designing of the magnetic functionalities of multiferroic hybrid perovskites and could provide an encouraging platform for the improvement of ab initio studies.