The Mechanism of the Magnetodielectric Response in a Molecule‐Based Trinuclear Iron Cluster Material

Abstract

Magnetodielectric response mechanisms are critical for the rational design and synthesis of molecule‐based magnetodielectric materials. Herein, the magnetodielectric response was investigated in the molecule‐based material [Fe3O(CH3COO)6(py)3](py) (1). Its magnetodielectric coefficient (MD) is −2.8 % for phase transition III and −4.1 % for phase transition I. Study of the mechanism of the magnetodielectric response in 1 reveals that its magnetodielectric response at phase transition I is induced by the charge‐frustration of the trinuclear iron cluster, while that at phase transition III is attributed to the spin‐frustration of the trinuclear iron cluster, providing a new route for the design of magnetodielectric materials.

Reversible Switchability of Magnetic Anisotropy and Magnetodielectric Effect Induced by Intermolecular Motion

“…When the magnetic field was applied along the crystallographic a axis of the single crystal, a small positive MD effect was observed in the LT phase at 200 and 250 K, but a much larger negative MD effect (−1.3%) was observed in the HT phase at 300 K. The magnitude of this value is smaller than the triethylmethylammonium tetrabromoferrate, the liquid crystal of a Co II compound, the trinuclear iron cluster, the Ni II chain, DyMnO 3 and DyMn 2 O 5 inorganic oxides, [39,49,51‐53,56] but is larger than the chiral Dy III SMM, the [(CH 3 ) 2 NH 2 ][Fe(HCOO) 3 ], the [C 6 H 5 CH 2 CH 2 NH 3 ] 2 [MCl 4 ], the TbFe 3 (BO 3 ) 4 and the Mn 3 O 4 inorganic oxides [47‐48,50,54‐55] . It is worth noting that most of the reported coordination compounds show a positive MD effect, [50‐57] while 1 displays the opposite by contrast. This suggests that the crystal lattice in 1 expands on increasing magnetic field while shrinks on demagnetizing.…”

Reversible Switchability of Magnetic Anisotropy and Magnetodielectric Effect Induced by Intermolecular Motion

“…When the magnetic field was applied along the crystallographic a axis of the single crystal, a small positive MD effect was observed in the LT phase at 200 and 250 K, but a much larger negative MD effect (−1.3%) was observed in the HT phase at 300 K. The magnitude of this value is smaller than the triethylmethylammonium tetrabromoferrate, the liquid crystal of a Co II compound, the trinuclear iron cluster, the Ni II chain, DyMnO 3 and DyMn 2 O 5 inorganic oxides, [39,49,51‐53,56] but is larger than the chiral Dy III SMM, the [(CH 3 ) 2 NH 2 ][Fe(HCOO) 3 ], the [C 6 H 5 CH 2 CH 2 NH 3 ] 2 [MCl 4 ], the TbFe 3 (BO 3 ) 4 and the Mn 3 O 4 inorganic oxides [47‐48,50,54‐55] . It is worth noting that most of the reported coordination compounds show a positive MD effect, [50‐57] while 1 displays the opposite by contrast. This suggests that the crystal lattice in 1 expands on increasing magnetic field while shrinks on demagnetizing.…”

“…Materials with a giant magnetic dielectric response and a magnetic field control at room (or higher) temperature are of great significance for practical applications such as capacitive resonators, magnetic sensors and actuators, read head in information storage, and biomedical devices [40–42] . In recent years, most single‐phase magnetodielectric materials are inorganics, [43–49] only a few of which are molecular magnets [50–57] . Nevertheless, as far as we know, the single‐crystal MD effect has not yet been explored in switchable molecular magnetic coordination compounds, let alone their synergistic changes of magnetic anisotropy and magnetodielectric effect.…”

Coupling Dielectric Functionality with Magnetic Properties in Coordination Metal Complexes

“…Zheng et al. reported an ME phenomenon in a mixed‐valence trinuclear Fe complex, [Fe 3 O(CH 3 COO) 6 (py) 3 ](py) (py=pyridine) (Figure 4), [68] which was investigated as a new MD material. Trinuclear oxo‐centered carboxylate complexes of Fe ions, exhibiting rapid electron hopping between Fe ions, are a suitable system for correlated spin/electron dynamics.…”