Magnetizing lead-free halide double perovskites

Abstract

Spintronics holds great potential for next-generation high-speed and low–power consumption information technology. Recently, lead halide perovskites (LHPs), which have gained great success in optoelectronics, also show interesting magnetic properties. However, the spin-related properties in LHPs originate from the spin-orbit coupling of Pb, limiting further development of these materials in spintronics. Here, we demonstrate a new generation of halide perovskites, by alloying magnetic elements into optoelectronic double perovskites, which provide rich chemical and structural diversities to host different magnetic elements. In our iron-alloyed double perovskite, Cs2Ag(Bi:Fe)Br6, Fe3+ replaces Bi3+ and forms FeBr6 clusters that homogenously distribute throughout the double perovskite crystals. We observe a strong temperature-dependent magnetic response at temperatures below 30 K, which is tentatively attributed to a weak ferromagnetic or antiferromagnetic response from localized regions. We anticipate that this work will stimulate future efforts in exploring this simple yet efficient approach to develop new spintronic materials based on lead-free double perovskites.

Lead‐Free Double Perovskite Cs2AgBiBr6: Fundamentals, Applications, and Perspectives

“…Cs 2 AgBiBr 6 displays a similar cubic double perovskite structure with a space group of Fm3m (lattice parameter 11.27 Å) at room temperature (RT). [14] This so-called rock salt ordering structure is formed by alternating corner-connected [AgBr 6 ] 5and [BiBr 6 ] 3octahedra in all three directions with Cs + located at the framework cavities (Figure 1b). The configuration of the octahedra, including the volume variation and distortion/tilting (mainly associated with bond lengths and bond angles), have a significant effect on the electronic structure and thus determine the optoelectronic properties of the perovskites.…”

“…[179,180] Now focus has begun to shift toward the lead-free Cs 2 AgBiBr 6 material system through the recent reports on the promising magnetic properties of Fe 3+ alloyed Cs 2 AgBiBr 6 . [14,42] Cs 2 Ag(Bi:Fe) Br 6 can be formed through a simple alloying process where magnetic Fe 3+ ions are distributed homogenously throughout a 3D Cs 2 AgBiBr 6 perovskite lattice as [FeBr 6 ] 3octahedra, replacing Bi 3+ ions. [14] We utilized electron spin resonance (ESR) in conjunction with a superconducting quantum interference device, to determine the perovskite's paramagnetic centers and identify ferromagnetic or antiferromagnetic resonance signals within the Cs 2 Ag(Bi:Fe)Br 6 crystals.…”

Experimental and Theoretical Investigation of the Structural and Opto‐electronic Properties of Fe‐Doped Lead‐Free Cs2AgBiCl6 Double Perovskite

“…Therefore, double perovskites materials are more attractive as they do not contain toxic Pb 2+ ions and have good thermal and chemical stability and band gap tunability. For example, bismuth halide double perovskites such as Cs 2 AgBiCl 6 and Cs 2 AgBiBr 6 have indirect band gaps of 2.77 eV and 1.95 eV, respectively [30–34] . Bandgap tunability has also been achieved by doping Mn 2+ , Sb 3+ , and In 3+ into the Cs 2 BiAgBr 6 lattice [35–38] .…”

“…For example, bismuth halide double perovskites such as Cs 2 AgBiCl 6 and Cs 2 AgBiBr 6 have indirect band gaps of 2.77 eV and 1.95 eV,r espectively. [30][31][32][33][34] Bandgap tunability has also been achieved by doping Mn 2 + ,S b 3 + ,a nd In 3 + into the Cs 2 BiAgBr 6 lattice. [35][36][37][38] For example, Locardi et al [25] have reportedh igh photoluminescence quantum yield (PLQY) and improved the visible light emission properties for Mn-doped Cs 2 AgInCl 6.…”

Highly Efficient Spin‐Filtering Transport in Chiral Hybrid Copper Halides

“…[17,27,28] Despite the high spin-selective efficiencies in lead-iodide HOIPs, lead-free organic-inorganic hybrid materials with strong air stability are still greatly desired for practical applications due to the Pb toxicity to the environment and organisms. [29,30] Comparing with p-zone metal elements (Pb, Sn, Bi) commonly used in HOIPs, most transition-metal hybrid perovskites are nontoxic with rich magnetic, [31][32][33] ferroelectric [34] and optical [35,36] properties. Copper(II) chloride hybridized with R-/S-methylbenzylammonium (R/S-MBA) has been synthesized and applied in the detection of circularly polarized light owing to the strong chiroptical activity.…”