Designing of a Magnetodielectric System in Hybrid Organic–Inorganic Framework, a Perovskite Layered Phosphonate MnO₃PC₆H₄‐m‐Br⋅H₂O

Abstract

Very few hybrid organic-inorganic framework (HOIF) exhibit direct coupling between spins and dipoles and are also restricted to a particular COOH-based system. It is shown how one can design a hybrid system to obtain such coupling based on the rational design of the organic ligands. The layered phosphonate, MnO 3 PC 6 H 5 ⋅H 2 O, consisting of perovskite layers stacked with organic phenyl layers, is used as a starting potential candidate. To introduce dipole moment, a closely related metal phosphonate, MnO 3 PC 6 H 4 -m-Br⋅H 2 O is designed. For this purpose, this phosphonate is prepared from 3-bromophenylphosphonic acid that features one electronegative bromine atom directly attached on the aromatic ring in the meta position, lowering the symmetry of precursor itself. Thus, bromobenzene moieties in MnO 3 PC 6 H 4 -m-Br⋅H 2 O induce a finite dipole moment. This new designedcompound exhibits complex magnetism, as observed in layered alkyl chains MnO 3 PC n H 2n+1 ⋅H 2 O materials, namely, 2D magnetic ordering ≈20 K followed by weak ferromagnetic ordering below 12 K (T 1 ) with a magnetic field (H)-induced transition ≈25 kOe below T 1 . All these magnetic features are exactly captured in the T and H-dependent dielectric constant, ε′(T) and ε′(H). This demonstrates direct magnetodielectric coupling in this designed hybrid and yields a new path to tune multiferroic ordering and magnetodielectric coupling.

M(H2O)(PO3C10H6OH)·(H2O)0.5 (M = Co, Mn, Zn, Cu): a new series of layered metallophosphonate compounds obtained from 6-hydroxy-2-naphthylphosphonic acid

“…This overall behavior can be ascribed to a canted antiferromagnetic ordering below 12.2 K as has been previously described for other Mn phosphonate layered compounds. 38,61,[63][64][65] The M vs. H curve ( Fig. 9) does not show opening of a hysteresis, as expected for canted antiferromagnets with a very small canting angle.…”

“…At low temperatures, χ = f (T ) presents a broad hump centered at 20 K, corresponding to 2D antiferromagnetic short range interactions. 38,61 The χ = f (T ) curve was fitted with a 2D high temperature series expansion for a square planar layer of Heisenberg spins S = 5/2 for T above 15 K (below this temperature, 3D correlations invalidate the model). 62 The fit leads to J = −1.9 cm −1 (considering a Hamiltonian in the form H ¼ ÀJ P ij S i Á S j ), in the same range as the exchange interactions reported for similar systems.…”

“…34,35 In a few cases, magneto-electric coupling was observed. [36][37][38] Since the properties of hybrid materials are influenced by the functionalization of organic precursors and after considering the incorporation of carboxylic acids 9 or halogen atoms into organic precursors 38,39 in addition to one or several phosphonic acid functions, 40 we investigate herein the conception of metal-phosphonate hybrids featuring phenol functions. Actually, only a few metal-phosphonate materials possessing phenol functions were previously reported in the literature.…”

Inorganic–Organic Hybrid Molecular Materials: From Multiferroic to Magnetoelectric

“…The MD coefficient of perovskite-structured [(CH 3 ) 2 NH 2 ]Cu(HCOO) 3 is only −0.06% at 5.2 K under a field of 7 T, while that of perovskite-structured [(CH 3 ) 2 NH 2 ]Fe(HCOO) 3 is much lower, −0.036% at 5 K under a field of 5 [CuCl 4 ] show low MD coefficients of 0.34% and 0.21% at 3 K under an applied field of 0.1 T, respectively. [103] Furthermore, the perovskite-layered phosphonate MnO 3 PC 6 H 4 -m-Br⋅H 2 O shows a low MD coefficient of 0.04% at 7 K under an applied field of 9 T. [104] It is worth noting that the [{Mn III (CH 2 (CN) 2 ) 2 (H 2 O) 2 }{Chloranil •− }]•(H 2 O) x radical shows a slightly higher value of −1.9% compared with those of the above-mentioned materials at room temperature under a lower field of 0.2 T. [102] In addition, the single-molecule magnet [Dy(L) 2 (C 2 H 5 OH)Cl 3 ]•C 2 H 5 OH (L = tricyclohexylphosphine oxide) shows a maximum MD coefficient of 0.75% at 2 K under an applied field of 9 T along the b-axis. [105] The MD effect is ascribed to the intrinsic spin-lattice coupling of the dysprosium(III) ion within the sample.…”

“…The MD parameters of selected inorganic-organic hybrid multiferroic materials are listed in Table 2. [83,35,40,72,[100][101][102][103][104][105][106][107] First, it can be observed that most multiferroic MOFs have a weak MD effect irrespective of the structure (perovskite-like structure, e.g., [(CH 3 ) 2 NH 2 ]Cu(HCOO) 3 [100] and [(CH 3 ) 2 NH 2 ]Fe(HCOO) 3 , [35] or tetragonal structure, e.g., [Co(C 16 H 15 N 5 O 2 )]), [101] further confirming the weak crosscoupling between the electric and magnetic orders in multiferroic MOFs. The MD coefficient of perovskite-structured [(CH 3 ) 2 NH 2 ]Cu(HCOO) 3 is only −0.06% at 5.2 K under a field of 7 T, while that of perovskite-structured [(CH 3 ) 2 NH 2 ]Fe(HCOO) 3 is much lower, −0.036% at 5 K under a field of 5 [CuCl 4 ] show low MD coefficients of 0.34% and 0.21% at 3 K under an applied field of 0.1 T, respectively.…”