Magnetic ferrites are spinel-structured transition-metal oxide-based nanoparticles that exhibit distinctive magnetic, electrical, and surface characteristics, rendering them highly promising materials for gas-sensing technologies. Rare-earth doping, particularly with lanthanum (La) and dysprosium (Dy), induces substantial alterations in crystal symmetry, electronic structure, defect chemistry, and magnetic behavior within the ferrite lattice. Such intrinsic modifications profoundly govern gas adsorption kinetics, surface reactivity, and charge-carrier transport, all of which are pivotal to achieving superior sensing performance. This review provides a rigorous and comprehensive evaluation of recent advances in La- and Dy-doped ferrite-based catalysts for gas sensors, with specific emphasis on synthesis strategies, structure-property correlations, sensing mechanisms, and key performance indicators. The analysis demonstrates that rare-earth incorporation improves sensitivity, selectivity, response stability, and thermal robustness through the generation of oxygen vacancies, modulation of grain-boundary characteristics, and enhancement of surface-active sites. The review finally concludes by outlining critical future research priorities and translational considerations for scalable, commercially viable sensor deployment.

Abstract
1. Introduction
2. Structural and Electronic Effects of Rare-Earth Doping in Ferrites
    2.1. Spinel Structure and Cation Distribution
    2.2. Oxygen Vacancies and Defect Chemistry
    2.3. Electronic and Magnetic Modifications
3. Gas Sensing Mechanism of Ferrite-BasedSensors
    3.1. Fundamentals of Gas Sensing
    3.2. Effect of Rare-Earth Dopants on SensingPerformance
4. Synthesis Strategies
    4.1. Sol-Gel Synthesis
    4.2. Co-precipitation Method
    4.3. Hydrothermal and Solvothermal Synthesis
    4.4. Auto-Combustion and Solid-State Reactions
    4.5. Spray Pyrolysis and Microwave-Assisted Synthesis
    4.6. Thin Film Deposition Techniques
5. Sensing Performance of La- and Dy-DopedFerrites
    5.1. Lanthanum-Doped Ferrites
    5.2. Dysprosium-Doped Ferrites
    5.3. Comparative Analysis and Synergistic Effects
6. Practical Considerations and Future Perspectives
7. Conclusion
Acknowledgement
References
Author Information

• Deepapriya Subramaniyan(PG and Research Department of Physics, Auxilium College (Autonomous), Vellore 632006, India)
• John David Rodney(Department of Advanced Components and Materials Engineering, Sunchon National University, Suncheon 57922, Republic of Korea)
• Byung Chul Kim(Department of Advanced Components and Materials Engineering, Sunchon National University, Suncheon 57922, Republic of Korea) Corresponding author
• Simon Edward Moulton(Department of Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia)