Enhanced Sensitivity of ZnFe₂O₄ Based on Ordered Magnetic Moment Induced by Magnetic Field: A New Insight into Mechanism

Abstract Semiconductor gas sensor mainly relies on the interaction between sensitive materials and gas to obtain gas information. Deep insight into the interaction mechanism is increasingly important for designing high performance gas sensors. Here, ZnFe₂O₄ microspheres (MSs) are utilized with tunable magnetism through the assistance of magnetic field to study the essential elements of sensitive processes. The gas sensing properties of ZnFe₂O₄ MS under different applied magnetic field intensities and various gaseous environments are systematically investigated. The results suggest that ordered magnetic moment induced by magnetic field promotes the probability of contact and reaction between gases and sensitive materials, thus significantly improving the sensitivity. Especially, ZnFe₂O₄ annealed at 500 °C sensor under the action of 54.6 mT magnetic field exhibits excellent ethanol detection performance (S = 67.8), which is ≈4 times higher than that without magnetic field. By carefully analyzing the experimental results, this research proposes a new physical model called “port docking” to re‐explain the sensitivity mechanism. This work systematically studies the role of the magnetic moment in the sensing process, and provides a new idea for designing high‐performance gas sensors.