Coexistence of magnetic and electrical order in the new perovskite-like (C3N2H5)[Mn(HCOO)3] formate

Abstract

In this work we further the structural characterization of the recently discovered (C 3 N 2 H 5 )[Mn(HCOO) 3 ] metal-organic framework with perovskite-like structure, and we present its magnetic and dielectric properties up to 350 K. At low temperature, the C 3 N 2 H 5 + imidazolium cations, that sit oblique within the cavities of the [Mn(HCOO) 3 ] À framework structure, show a cooperative order resulting in an antiparallel arrangement of their electrical dipole moments. Very interestingly, it is only above 220 K that thermal energy seems to be able to break this antiferroelectric order, resulting in a linear increase of its dielectric constant with temperature. In addition, this Mn(II) compound is antiferromagnetic below T N ¼ 9 K, with a slightly non-collinear arrangement of its magnetic moments, yielding to a weak ferromagnetism. Therefore, this is a new multiferroic material which exhibits coexistence of magnetic and electric ordering. † Electronic supplementary information (ESI) available: Structural details; results of Le Bail renement of powder X-ray diffraction; DSC curve; ts of the c m (T) data; observed frequencies in cm À1 of the Raman spectra at 100 K and suggested assignments. The cif les with the structural information obtained by single crystal X-ray diffraction. CCDC 959632 and 959633. For ESI and crystallographic data in CIF or other electronic format see

Synthesis and order–disorder transition in a novel metal formate framework of [(CH3)2NH2]Na0.5Fe0.5(HCOO)3]

“…Such a small canting is in general strongly sensitive to temperature, magnetic field and the strength of the coupling between the magnetic ions, and small changes in these parameters may lead to complex magnetic behavior. 18 The small saturation magnetization of DMNaFe, comparable to that found in other metal formates templated by dimethylammonium, 8,9 ammonium, 3 or imidazolium, 19 is consistent with the spin-canted mechanism of the long-range magnetic ordering in DMNaFe.…”

“…22 Here it is interesting to note that order-disorder phase transitions in the family of perovskite-type MOFs of formula [cat][M(HCOO) 3 ], where cat denotes an organic cation, were reported for cat = DMA + , azetidinium, formamidinium, imidazolium, hydrazinium, or ethylammonium. 6,7,9,11,12,19,21,26 For the manganese analogues, the phase transition temperature upon cooling was the lowest for DMA + (181 K) and the highest for imidazolium (435 K), 9,19 and Fig. 7 Raman spectra in the spectral range 25-500 cm −1 .…”

Polarized IR and Raman spectra of the novel metal-organic framework [CH3CH2NH3][Cd(HCOO)3]

“…Many of [cat][M(HCOO)3] compounds undergo structural phase transitions, which are often associated with the appearance of electric order and pronounced dielectric anomalies [8][9][10][11][12][13][14][15][16][17]. It is worth to mention that up to now the highest phase transition temperature (435 K) in the family of dense MOFs has been found for imidazolium analogue, [C3N2H5][Mn(HCOO)3] [14].…”

“…The best known examples are compounds of general formula [cat][M(HCOO)3], where M = Mn, Ni, 3 Co, Fe, and cat denotes ammonium, methylammonium, dimethylammonium (DMA), guanidinium (Gua), formamidinium (FMD) or azetidinium cation [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Many of [cat][M(HCOO)3] compounds undergo structural phase transitions, which are often associated with the appearance of electric order and pronounced dielectric anomalies [8][9][10][11][12][13][14][15][16][17]. It is worth to mention that up to now the highest phase transition temperature (435 K) in the family of dense MOFs has been found for imidazolium analogue, [C3N2H5][Mn(HCOO)3] [14].…”

Cross coupling between electric and magnetic orders in a multiferroic metal-organic framework

“…In 2009, Jain et al reported a multiferroic behavior in a family of perovskite MOFs8. This finding has stimulated considerable experimental and theoretical efforts to search for new multiferroic materials in MOFs910112324252627282930. However, the cross coupling between magnetic and electric orders in MOFs, an extremely important feature required for applications, has not been verified in previous studies, which has casted doubt on the promise of organic multiferroics.…”