NaBH 4 induces strong ferromagnetism of Bi 2 Fe 4 O 9 at room temperature

Abstract Bi 2 Fe 4 O 9 nanosheets were prepared using a hydrothermal method, followed by the introduction of NaBH 4 and high-temperature calcination, which successfully induced strong ferromagnetism in the material at room temperature ( M S = 10.22 emu/g and M r = 2.93 emu/g). This work demonstrates for the first time that Bi 2 Fe 4 O 9 can exhibit such strong ferromagnetism at room temperature, with potential for further enhancements. Meanwhile, the ferroelectric properties of the samples were investigated. X-ray diffraction confirmed that the samples were single-phase with no detectable impurities. Based on a series of characterization analyses, it is inferred that Bi vacancies contribute to the observed strong magnetism.