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.

Background: Chronic nausea in adolescents with functional gastrointestinal disorders is an increasingly reported but poorly understood symptom that negatively affects quality of life. Functional gastrointestinal disorders are known to correlate closely with slow wave rhythm disturbances. The ability to characterize gastric electrophysiologic perturbations in functional nausea patients could provide potential diagnostic and therapeutic tools for nausea patients. Methods:We used high-resolution electrogastrograms (HR-EGG) to measure gastric slow wave parameters in pediatric chronic nausea patients and healthy subjects both pre-and postprandial. We computed the dominant frequency, percentage power distribution, gastric slow wave propagation direction, and speed from HR-EGG. Key Results:We observed significant differences in the dominant frequency and power distributed in normal and bradyarrhythmia frequency ranges when comparing patients and healthy subjects. Propagation patterns in healthy subjects were predominantly anterograde, while patients exhibited a variety of abnormalities including retrograde, anterograde, and disrupted patterns. There was a significant difference in the preprandial mean slow wave direction between healthy subjects (222° ± 22°) and patients (103° ± 66°; p ˂ 0.01), although the postprandial mean direction between healthy subjects and patients was similar (p = 0.73). No significant difference in slow wave propagation speed was found between patients and healthy subjects in either pre-(p = 0.21) or postprandial periods (p = 0.75). Conclusions and Inferences:The spatiotemporal characterization of gastric slow wave activity using HR-EGG distinguishes symptomatic chronic nausea patients from healthy subjects.This characterization may in turn inform and direct clinical decisionmaking and lead to further insight into its pathophysiology.

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Hybrid magnonic systems are a newcomer for pursuing coherent information processing owing to their rich quantum engineering functionalities. One prototypical example is hybrid magnonics in antiferromagnets with an easy-plane anisotropy that resembles a quantum-mechanically mixed two-level spin system through the coupling of acoustic and optical magnons. Generally, the coupling between these orthogonal modes is forbidden due to their opposite parity. Here we show that the Dzyaloshinskii–Moriya-Interaction (DMI), a chiral antisymmetric interaction that occurs in magnetic systems with low symmetry, can lift this restriction. We report that layered hybrid perovskite antiferromagnets with an interlayer DMI can lead to a strong intrinsic magnon-magnon coupling strength up to 0.24 GHz, which is four times greater than the dissipation rates of the acoustic/optical modes. Our work shows that the DMI in these hybrid antiferromagnets holds promise for leveraging magnon-magnon coupling by harnessing symmetry breaking in a highly tunable, solution-processable layered magnetic platform.