Structural, magnetic and evanescent wave gas sensing analysis of spin-frustrated rare earth doped Bi2Fe4O9 mullite ceramics at room temperature

This study investigates the gas sensing capabilities of bulk Bi2(1-x)La2xFe4O9 with x = 0, and 0.05 systems (BFO 0, BLFO 5), using a fiber optic VOC sensor at room temperature. Structural and magnetic characterizations confirm the successful incorporation of La3+ into the Bi site of the BFO 0 lattice without altering the structure. BLFO 5 exhibits remarkable gas sensitivity towards benzene, with a normalized gas sensitivity of 47 counts/100 ppm. This enhanced sensitivity is attributed to the presence of oxygen vacancies, which contribute to BLFO 5's weak ferromagnetism. The rapid response (43 s) and recovery (51 s) times further demonstrate the promising potential of multiferroic materials for VOC detection.