Magnetic Ordering-Induced Multiferroic Behavior in [CH₃NH₃][Co(HCOO)₃] Metal–Organic Framework

Abstract

We present the first example of magnetic ordering-induced multiferroic behavior in a metal-organic framework magnet. This compound is [CH3NH3][Co(HCOO)3] with a perovskite-like structure. The A-site [CH3NH3](+) cation strongly distorts the framework, allowing anisotropic magnetic and electric behavior and coupling between them to occur. This material is a spin canted antiferromagnet below 15.9 K with a weak ferromagnetic component attributable to Dzyaloshinskii-Moriya (DM) interactions and experiences a discontinuous hysteretic magnetic-field-induced switching along [010] and a more continuous hysteresis along [101]. Coupling between the magnetic and electric order is resolved when the field is applied along this [101]: a spin rearrangement occurs at a critical magnetic field in the ac plane that induces a change in the electric polarization along [101] and [10-1]. The electric polarization exhibits an unusual memory effect, as it remembers the direction of the previous two magnetic-field pulses applied. The data are consistent with an inverse-DM mechanism for multiferroic behavior.

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

“…The IR reflection spectra of the 13 EtACd crystal have been fitted using the four-parameter model. Information about LO and TO wavenumbers can be received from fitting the IR reflection spectra by using a fourparameter model [40].…”

“…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].…”

Giant barocaloric effect in the ferroic organic-inorganic hybrid [TPrA][Mn(dca)3] perovskite under easily accessible pressures

“…Remarkable examples are, for instance, (CH 3 NH 3 )PbI 3 and related compounds2526, which exhibit exceptional optoelectronic properties for photovoltaic applications. And also the [AmineH][M(X) 3 ] perovskite families (AmineH=midsized protonated amines, M=divalent transition metal cations, X=bidentate-bridge ligands HCOO − , N 3 − , CN − , and so on) which display outstanding functionalities such as cooperative magnetic, electric and/or elastic order, and magnetically induced multiferroicity; moreover, they can also act as precursors for different nanostructured functional materials272829303132333435363738.…”

A multiferroic material [NH2-CH+-NH2]Co(HCOO)3 of metal-organic frameworks with weak ferromagnetism and dielectric relaxation

“…7,8 In perovskite MOFs compounds, the electronic and magnetic properties associated with order/disorder transitions of the [AmineH] + cations and the framework [M(HCOO) 3 ] -, respectively. [9][10][11] So the perovskite MOFs materials can be suitable candidates, as single-phase multiferroic materials with excellent electronic and magnetic properties. [12][13][14][15][16] It has been reported that the MOFs materials with different A (different size, type) exhibit different physical properties.…”

“…[21][22][23] The property of ferroelectricity induced by magnetic order was also found in the metal-organic framework magnet [CH 3 NH 3 ][Co(HCOO) 3 ]. 9,24 Recently, Ren-Gen Xiong and his team reported that the para-toferroelectricity occurred in range of 3 ] series, which the disorder-order transition of (CH 3 ) 2 NH 2 + template could be the origin of electric ordering. 25,26 On the other hand, the magnetoelectric effect could exist in the materials with the A of C(NH 2 ) 3 However, the disorder-order transition usually appears at very low temperature among these MOFs materials.…”