Formate-mediated magnetic superexchange in the model hybrid perovskite [(CH3)2NH2]Cu(HCOO)3

Rebecca Scatena,Pascal Manuel,Piero Macchi,Roger D Johnson

doi:10.1039/d0tc03913f

Abstract

The hybrid-perovskite [(CH3)2NH2]Cu(HCOO)3 shows antiferromagnetic and ferromagnetic interactions, as predicted by the GKA rules, proven applicable by experimental charge-density analysis.

Highlights

We have investigated the magnetic and electronic structures of crystalline dimethylammonium copper formate [(CH3)2NH2]Cu(HCOO)[3], a model compound that belongs to a wide class of hybrid organic– inorganic perovskites
We present the results of a combined experimental approach, where neutron diffraction and magnetisation measurements were used to solve the ground state magnetic structure in which the same ligand mediates both antiferromagnetic and ferromagnetic interactions, while the electron charge density distribution and orbital occupancy were determined by high-resolution X-ray diffraction
We have explored the relationships between structure and magnetic properties in [(CH3)2NH2]Cu(HCOO)3 [dimethylammonium copper formate (DMACuF)] – a canonical hybrid organic–inorganic perovskite.[14,15,16]

Summary

Introduction

Compared to the inorganic transition metal oxide perovskites, hybrid organic–inorganic coordination polymers are a relatively young class of materials in which a transition metal is coordinated by polydentate organic ligands forming extended periodic structures.[6]. Based on the field dependence of the magnetic susceptibility below TN, and the fact that AFM coupling is normally observed for SE interactions mediated by molecular building blocks, Jeq–ax has been reported to be AFM.[17] Alternatively, based on the foundational Goodenough–Kanamori–Anderson (GKA) rules[18,19,20] taken from inorganic perovskite research,[21] and density functional theory (DFT) studies,[16] Jeq–ax has been reported to be ferromagnetic (FM) Confirming the latter case would demonstrate that formate ligands can be used to mediate both FM and AFM superexchange. Candidate magnetic structure models were established by symmetry analysis performed using ISODISTORT,[23] which were systematically tested against the data obtained from the difference between the patterns collected at 1.5 K and 10 K (Fig. 3). The simulated electron density distribution was used to obtain a calculated structure factor that was fitted to the MM by using XD201626 and the result was analysed using the XDPROP and TOPXD modules

Results and discussion

Conflicts of interest

Conclusions