Chemical Control of Magnetic Ordering in Hybrid Fe–Cl Layered Double Perovskites

Abstract

Recent discoveries of novel physics in two-dimensional (2D) magnetic materials have sparked the search of new layered magnetic semiconductors. Compared to the traditional inorganic 2D van der Waals crystals, hybrid organic–inorganic metal–halide frameworks offer significantly enhanced chemical and structural versatility, where their optical, electronic, and magnetic properties can be readily modulated with both organic and inorganic components. Here, we reported a series of new Fe–Cl-based layered double perovskites L n MIMIIICl8, [n = 4, L = phenylethylammonium or chiral R-(+)-β-methylphenethylammonium and n = 2, L = 1,4-butanediammonium; MI = Ag/Na; MIII = Fe/In]. UV–vis measurements show that their optical band gaps are highly tunable by varying the organic cations, MI ion, and MIII ion. Magnetic susceptibility measurements suggest an antiferromagnetic coupling between the nearest FeIII–FeIII, where the Curie–Weiss temperature, Néel temperature, and frustration factors can be easily modulated with their compositions and dimensionality. Our study demonstrates the rich and interesting magnetic properties in these layered transition-metal–halide double perovskites and paves the way for design of multifunctional magnetic materials.

Magnetic Properties of Layered Hybrid Organic‐Inorganic Metal‐Halide Perovskites: Transition Metal, Organic Cation and Perovskite Phase Effects

“…[21][22][23] So far, comparatively few works have sought to explore and understand their magnetic properties. [14] Those that have, revealed a rich phenomenology: depending on the transition metal ion (Cu 2+ , [24][25][26][27][28][29][30][31][32][33][34][35][36] Cr 2+ , [13] Mn 2+ , [28,[37][38][39][40][41] Fe 2+ , [42][43][44][45] Co 2+ , [28,46] Ru 3+ , [47] and Mo 3+ [47] ), the HOIP can exhibit ferromagnetic (FM), antiferromagnetic (AFM), coexistence of FM/ AFM, [33] paramagnetic, or no magnetic ordering at all. [47] In contrast, other hybrid perovskite-type magnetic materials such as metal-formates [14,[48][49][50] and hypophosphites [51] have shown less magnetic tunability by chemical design.…”

“…These differences translate into local lattice distortions and variations in the length and angles of the X⋯M⋯X bonds, which in turn affect the resulting magnetic behavior. [14,18,45,52] Moreover, the hydrogen bonding between the inorganic and organic parts in layered HOIPs induces a complex interaction between structural deformation of the octahedra and the conformational flexibility of the organic cations, leading to the appearance of structural phase transitions. [53][54][55][56] In some cases, the emerging crystal phases exhibit new properties, such as ferroelectricity [26,57] and ferroelasticity.…”

Water-driven Successive Structural Transformation in a Two-Dimensional (2D) Lead-Free Hybrid Double Perovskite

“…Besides, most of the reported 2D perovskites mainly focused on Pb 2+ and Sn 2+ divalent ions. , Recently, divalent ions (M 2+ ) were replaced by one monovalent cation (M + ) and another trivalent cation (M 3+ ) . Under such a trend, several types of double perovskites, such as Ag–Bi − /In/Ru, Na–Fe, and Cu–Bi, have been discovered.…”

Halide Double-Perovskite Semiconductors beyond Photovoltaics

“…We suspect that the incorporation of large organic moieties to induce the formation of two-dimensional (2D) halide double perovskites has huge potential, since specific functionalized spacers 70 (e.g., photoactive, electroactive, chiral) that are responsive to various stimuli can serve as platforms for advanced functions in future smart nanotechnologies. 69 …”

“…Colloidal quantum dots and nanostructures of the most promising halide double perovskites could be used to further tune the optoelectronic properties and the stability of such materials . Finally, although some 2D compositions have been recently reported, systematic and representative explorations on this class of materials are still largely underrepresented. We suspect that the incorporation of large organic moieties to induce the formation of two-dimensional (2D) halide double perovskites has huge potential, since specific functionalized spacers (e.g., photoactive, electroactive, chiral) that are responsive to various stimuli can serve as platforms for advanced functions in future smart nanotechnologies …”