Magnetic resonance probing of ferroelectricity and magnetism in metal-organic frameworks

International audienceWe employ electron paramagnetic resonance (EPR) of the spin probe Mn 2þ to study the paraelectric À ferroelectric transition in Dimethylammonium Manganese Formate (DMMnF) and Mn 2þ-doped Dimethylammonium Zinc Formate (DMZnF), which are considered model metal À organic frameworks (MOF) with a Pb-free perovskite architecture. In DMMnF, we study the variation of the Mn 2þ EPR line shape and intensity at the X-band ($9.4 GHz) and over 80 to 300 K, and we show the absence of magnetoelectric coupling at the ferro-electric transition. At the antiferromagnetic transition in DMMnF, we detect a magnetoelectric coupling caused by weak ferromagnetism in the AFM phase. In DMZnF, EPR spectra of the Mn 2þ probe combined with DFT show that the crystal field is predominantly determined by the Dimethylammonium (DMA þ) cations. ARTICLE HISTOR