Development of a New Type of Magneto-optical Material: Flexible, Low-Cost, Fe<sub>3</sub>O<sub>4</sub>@ZIF-8/PgC<sub>5</sub>Cu/PMMA with High Figure of Merit.

Lin, Yuling; Zhang, Pengpai; Zhang, Bowen; Zhang, Ying; Xie, Jiafang; Wang, Cheng; Wu, Junying; Wang, Ziwei et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Magneto-optical materials are essential for optical communication devices, yet most crystalline or vitreous media are rigid and have high demands on design and processing. Here we develop a facile multicomponent composite strategy to fabricate a flexible magneto-optical film, Fe<sub>3</sub>O<sub>4</sub>@ZIF-8/PgC<sub>5</sub>Cu/PMMA, where ultrasmall Fe<sub>3</sub>O<sub>4</sub> magnetic units are uniformly embedded in a transparent polymer. The film loaded with 0-1.5 wt % Fe<sub>3</sub>O<sub>4</sub>@ZIF-8/PgC<sub>5</sub>Cu has flexible, readily formable, and high magneto-optical properties while maintaining a high optical transmittance of about 80%. Another encouraging result is that a common magnetic material of Fe<sub>3</sub>O<sub>4</sub> composite is clearly observed to have strong magneto-optical effect. At 0.5 wt %, the figure of merit reaches 6 deg.·dB<sup>-1</sup> at 532 nm, exceeding that of Bi:YIG/PMMA (1.46 deg.·dB<sup>-1</sup>). Moreover, the magnetic circular dichroism at 532 nm exceeds 7 times that of commercial crystalline YIG. This work offers a promising strategy to fabricate flexible magneto-optical materials, expanding applications in microscale devices of specific shapes.