Hexaferrite materials emerge as multifunctional materials with effective magnetic and microwave absorption properties, which contribute to modern electrical mobility and radar applications. In this work, we present a comprehensive analysis of the BaFe12-xAlxO19 (x = 0.00, 0.02, 0.04, 0.06, and 0.08) series, synthesized via the citrate precursor route. Structural and Fourier transform infrared (FTIR) analysis established the M-type hexagonal phase for all studied compounds. Magnetic results reveal the hard ferromagnetic nature of the investigated compounds. In addition, crystallographic parameters, metal-oxygen stretching, bending vibrations, and magnetic characteristic parameters were also tuned with the doping concentration. Besides, microwave absorption behavior in terms of complex permittivity and permeability across different target bands is also examined. The result divulges the synergistic effects of dielectric/magnetic loss and strong electromagnetic attenuation, enabling efficient microwave absorption/reflection loss, a wide effective absorption bandwidth, and a thin matching thickness. The reported results demonstrate that tuning the nonmagnetic Al3+ doping in M-type hexaferrites provides an effective avenue to alter the magnetic and microwave absorption properties, suggesting its potential in communication technology.
References
[1]
Mahanta, A., Samal, R. and Sahu, N.C. (2026) Harnessing Renewable Energy to Advance Sustainable Tourism and Green Growth: A G20 Countries’ Perspective. Energy Research Letters, 7, 1-6. https://doi.org/10.46557/001c.156401
[2]
Rasool, H., Maqbool, S. and Tarique, M. (2021) The Relationship between Tourism and Economic Growth among BRICS Countries: A Panel Cointegration Analysis. Future Business Journal, 7, Article No. 1. https://doi.org/10.1186/s43093-020-00048-3
[3]
You, W., Zhang, Y. and Lee, C. (2021) Climate Risk, Economic Stability, and Tourism: A Cross-Sectionally Dependent Heterogeneous Panel Causality Analysis. Energy Research Letters, 2, 1-5. https://doi.org/10.46557/001c.25723
[4]
Rangarajan, S.S., Shiva, C.K., Collins, E.R. and Senjyu, T. (2025) Electric Vehicle Motors Free of Rare-Earth Elements—An Overview. Machines, 13, Article 702. https://doi.org/10.3390/machines13080702
[5]
Mohammed, I., Mohammed, J. and Srivastava, A.K. (2022) Recent Progress in Hexagonal Ferrites Based Composites for Microwave Absorption. Crystal Research and Technology, 58, Article ID: 2200200. https://doi.org/10.1002/crat.202200200
[6]
Riba, J., López-Torres, C., Romeral, L. and Garcia, A. (2016) Rare-Earth-Free Propulsion Motors for Electric Vehicles: A Technology Review. Renewable and Sustainable Energy Reviews, 57, 367-379. https://doi.org/10.1016/j.rser.2015.12.121
[7]
Dippong, T. (2021) Characterization and Applications of Metal Ferrite Nanocomposites. Nanomaterials, 12, Article 107. https://doi.org/10.3390/nano12010107
[8]
Vidya, Y.S., Manjunatha, H.C., Sridhar, K.N., Seenappa, L., Munirathnam, R. and Chinnappareddy, B. (2023) Brief Review on Magnetic Properties of Nanoferrites. Inorganic Chemistry Communications, 158, Article ID: 111408. https://doi.org/10.1016/j.inoche.2023.111408
[9]
Majeed, A., Khan, M.A., Ahmad, A., Javed, Z., Lodhi, M.Y., Khan, S., et al. (2025) Promising X-Type Hexagonal Ferrites for High Frequency Applications; Synthesis and Characterizations. Ceramics International, 51, 32305-32317. https://doi.org/10.1016/j.ceramint.2025.04.417
Irfan, M., Shamshad, I., Ashiq, A.R., Shabbir, H.G., Idrees, T., Khan, F., et al. (2025) A Critical Review on Structural, Magnetic, and Electrical Properties of R-Type Hexaferrites for Microwave Applications. Next Materials, 9, Article ID: 101204. https://doi.org/10.1016/j.nxmate.2025.101204
[12]
Dehghani Dastjerdi, O., Shokrollahi, H. and Mirshekari, S. (2023) A Review of Synthesis, Characterization, and Magnetic Properties of Soft Spinel Ferrites. Inorganic Chemistry Communications, 153, Article ID: 110797. https://doi.org/10.1016/j.inoche.2023.110797
[13]
Chang, T. (2020) Ferrite Materials and Applications. In: Han, M.G., Ed., Electromagnetic Materials and Devices, IntechOpen, 137-349. https://doi.org/10.5772/intechopen.84623
[14]
Sharma, D., Rohit, Singh, V., Dogra, A. and Singh, M. (2024) Aluminium and Praseodymium Doped M-Type Hexaferrites for Electric Vehicle Applications. Ceramics International, 50, 24815-24822. https://doi.org/10.1016/j.ceramint.2024.04.217
[15]
Duglet, R., Chauhan, A., Sharma, D., Thakur, A. and Singh, M. (2024) Investigation on Microwave Absorption Properties of Bismuth Ions Doped Barium Hexaferrites. Journal of Materials Science: Materials in Electronics, 35, Article No. 654. https://doi.org/10.1007/s10854-024-12418-6
[16]
Chandel, M., Pratap Singh, V., Jasrotia, R., Singha, K. and Kumar, R. (2020) A Review on Structural, Electrical and Magnetic Properties of Y-Type Hexaferrites Synthesized by Different Techniques for Antenna Applications and Microwave Absorbing Characteristic Materials. AIMS Materials Science, 7, 244-268. https://doi.org/10.3934/matersci.2020.3.244
[17]
Pullar, R.C. (2012) Hexagonal Ferrites: A Review of the Synthesis, Properties and Applications of Hexaferrite Ceramics. Progress in Materials Science, 57, 1191-1334.
[18]
Shepherd, P., Mallick, K.K. and Green, R.J. (2007) Magnetic and Structural Properties of M-Type Barium Hexaferrite Prepared by Co-Precipitation. Journal of Magnetism and Magnetic Materials, 311, 683-692. https://doi.org/10.1016/j.jmmm.2006.08.046
[19]
Kaur, H., Bhatia, K.S., Tewari, B.S., Mandal, P. and Dhyani, A. (2022) Influence of Co-In Doping in M-Type Barium-Strontium Hexagonal Ferrite on Microwave Absorption. Journal of Electronic Materials, 51, 4152-4160. https://doi.org/10.1007/s11664-022-09731-3
[20]
Liao, W., Huang, K., Xu, W., Yu, J., Li, P. and Xu, J. (2024) Broadband Microwave Absorption and Electromagnetic Properties of Gd-Al-Co-Doped M-Type Barium Hexaferrite in 2-18 GHz Range. Journal of Magnetism and Magnetic Materials, 612, Article ID: 172609. https://doi.org/10.1016/j.jmmm.2024.172609
[21]
Naqvi, S.T.A., Godara, S.K., Ray, B., Datar, S. and Singh, C. (2025) Tunable Structural, Magnetic, Complex Permittivity/Permeability, and Reflection Loss Parameters of Co2+ and Ni2+-Co-Doped M-Type Strontium Ferrites for Microwave Absorber Applications. Journal of Materials Science: Materials in Electronics, 36, Article No. 213. https://doi.org/10.1007/s10854-025-14252-w
[22]
Abbas, W., Ahmad, I., Kanwal, M., Murtaza, G., Ali, I., Azhar Khan, M., et al. (2015) Structural and Magnetic Behavior of Pr-Substituted M-Type Hexagonal Ferrites Synthesized by Sol-Gel Autocombustion for a Variety of Applications. Journal of Magnetism and Magnetic Materials, 374, 187-191. https://doi.org/10.1016/j.jmmm.2014.08.029
[23]
Mahmoud, M.H., Hassan, A.M., Said, A.E.A. and Taha, T.A. (2022) Structural, Magnetic, and Catalytic Studies of Microwave-Combustion/Ball-Mill Synthesized Zinc Ferrite Nanoparticles. Inorganic Chemistry Communications, 144, Article ID: 109932. https://doi.org/10.1016/j.inoche.2022.109932
[24]
Yasin, S.M. (2023) Superparamagnetic Ni0.5Zn0.5Fe2O4 Nanoparticles Prepared by Ball-Milling. Applied Physics A, 129, Article No. 672. https://doi.org/10.1007/s00339-023-06954-x
[25]
Piotto, V., et al. (2022) Synthesis of Magnetic Nanoparticles by Laser Ablation of Strontium Ferrite under Water and Their Characterization by Optically Detected Magnetophoresis Supported by BEM Calculations. Journal of Materials Chemistry C, 10, 3819-3825.
[26]
Saremi, A., Mirkazemi, S.M., Sazvar, A. and Rezaie, H. (2024) Controlling Magnetic and Surface Properties of Cobalt Ferrite Nanoparticles: A Comparison of Co-Precipitation and Solvothermal Synthesis Methods. Solid State Sciences, 148, Article ID: 107432. https://doi.org/10.1016/j.solidstatesciences.2023.107432
[27]
Moatoshi, Sah, S.K., Kaushik, S.D. and Borah, J.P. (2024) Structural and Magnetic Properties of M-Type Hexaferrite Nanoparticles: A Comparative Analysis of BaFe12O19 and SrFe12O19 Synthesized via Chemical Co-Precipitation. Ceramics International, 50, 22599-22607. https://doi.org/10.1016/j.ceramint.2024.03.361
[28]
Wang, X., Wang, B., Wei, S., Wang, Y. and Liang, Y. (2023) Effect of Sintering Temperature on the Microstructure, Magnetic, and Microwave Absorption Properties of M-Type Barium Ferrite Nanoparticles Prepared by Sol-Gel Method. Journal of Materials Science: Materials in Electronics, 34, Article No. 1045. https://doi.org/10.1007/s10854-023-10400-2
[29]
Borhan, A.I., Iordan, A.R., Gherc？, D. and Palamaru, M.N. (2023) Ferrite Nanoparticles by Sol-Gel Method. In: Singh, J.P., Chae, K.H., Srivastava, R.C. and Caltun, O.F., Eds., Ferrite Nanostructured Magnetic Materials, Elsevier, 103-119. https://doi.org/10.1016/b978-0-12-823717-5.00047-4
[30]
Sharma, I., Vineet Sharma, M. and Sharma, P. (2022) A Review on Synthesis and Characterization of MnZn Ferrite Nanoparticles via Citrate Precursor Method. Peer Reviewed and Refereed Journal, 11, 57-67.
[31]
Sharma, D., Duglet, R., Singh, V., Mohd, Y., Dogra, A. and Singh, M. (2026) Tailoring Magnetic Parameters of M-Type Hexaferrites via Nd-Al Doping for Rare Earth Free Permanent Magnet in Ev’s. Physics Letters A, 579, Article ID: 131517. https://doi.org/10.1016/j.physleta.2026.131517
[32]
Pandav, R.S., Pujari, S.S., Bagade, A.A., Gurme, V.M. and Sankpal, U.B. (2026) Structural, Magnetic, and Dielectric Properties of Cr Substituted Cobalt Ferrite Nanoparticles Synthesized by Citrate-Gel Auto-Combustion. Journal of Materials Science: Materials in Electronics, 37, Article No. 458. https://doi.org/10.1007/s10854-026-16888-8
[33]
Liaquat, A., Anis-ur-Rehman, M. and ul Haq, A. (2020) Impact of Gd Doping on the Dielectric and Magnetic Properties of (Sr-ba) Fe12o19 Nanoparticles. Journal of Alloys and Compounds, 822, Article ID: 153561. https://doi.org/10.1016/j.jallcom.2019.153561
[34]
Gulbadan, S., Khan, M.A., Rasool, R.T., Zelai, T., Mahmood, K., Shahid, M., et al. (2023) Investigation of Crystal Structure, Photoluminescence, and Raman Studies of Sm-Co Substituted Ba-Sr M-Type Hexaferrites. Ceramics International, 49, 18076-18083. https://doi.org/10.1016/j.ceramint.2023.02.176
[35]
Mohammed, J., Suleiman, A.B., Hafeez, H.Y., Carol T, T.T., Sharma, J., Bhadu, G.R., et al. (2018) Effect of Heat-Treatment on the Magnetic and Optical Properties of Sr0.7Al0.3Fe11.4Mn0.6O19. Materials Research Express, 5, Article ID: 086106. https://doi.org/10.1088/2053-1591/aad1e5
[36]
Godara, S.K., Kaur, M.P., Kaur, V., Malhi, P.S., Singh, M., Verma, S., et al. (2022) Investigation of Microstructural and Magnetic Properties of Ca2+ Doped Strontium Hexaferrite Nanoparticles. Journal of King Saud University—Science, 34, Article ID: 101963. https://doi.org/10.1016/j.jksus.2022.101963
[37]
Carol, T.T.T., et al. (2025) Crystal Structure Refinement, Bond Length, Raman Spectroscopy and Magnetic Properties of Al3+-and Ce3+-Codoped M-Type Barium Hexagonal Ferrite. Inorganic Chemistry Communications, 173, Article ID: 113771.
[38]
Luo, H., Rai, B.K., Mishra, S.R., Nguyen, V.V. and Liu, J.P. (2012) Physical and Magnetic Properties of Highly Aluminum Doped Strontium Ferrite Nanoparticles Prepared by Auto-Combustion Route. Journal of Magnetism and Magnetic Materials, 324, 2602-2608. https://doi.org/10.1016/j.jmmm.2012.02.106
[39]
Cullity, B.D. (1978) Elements of X-Ray Diffraction. Addison-Wesley Publishing Company.
[40]
Xu, W., Liao, W., Zhou, H., Wang, L., Huang, K., Li, P., et al. (2024) M-Type Ba-Hexaferrite Nanoplates with Exceptional Microwave Absorption Properties. ACS Applied Electronic Materials, 6, 2759-2766. https://doi.org/10.1021/acsaelm.4c00307
[41]
Verma, R., Chauhan, A., Batoo, K.M., Kumar, R., Hadi, M. and Raslan, E.H. (2021) Structural, Morphological, and Optical Properties of Strontium Doped Lead-Free BCZT Ceramics. Ceramics International, 47, 15442-15457. https://doi.org/10.1016/j.ceramint.2021.02.110
[42]
Gilani, Z.A., Ul Islam, S., Khan Asghar, H.M.N.U.H., Hussain, R. and Ahmad Shaikh, F. (2021) Impact of Lanthanum Doping on the Structural, Electrical, and Magnetic Properties of BaFe12O19 Nano Particles. Journal of Materials and Physical Sciences, 2, 22-32. https://doi.org/10.52131/jmps.2021.0201.0013
[43]
Naqvi, S.T.A., Godara, S.K., Ray, B., Datar, S. and Singh, C. (2025) Investigation of Structural, Hysteresis, and Microwave Dielectric/Magnetic Properties of Co-Zn Doped M-Type Strontium Hexaferrites for Light-Weight Microwave Absorber Applications. Emergent Materials, 8, 3331-3353. https://doi.org/10.1007/s42247-025-01034-7
[44]
Sertkol, M., K？seo？lu, Y., Baykal, A., Kavas, H., Bozkurt, A. and Toprak, M.S. (2009) Microwave Synthesis and Characterization of Zn-Doped Nickel Ferrite Nanoparticles. Journal of Alloys and Compounds, 486, 325-329. https://doi.org/10.1016/j.jallcom.2009.06.128
[45]
Atkare, S.S., Shirsath, S.E., Batoo, K.M., Ijaz, M.F., Deshmukh, V.J., Kadam, R.H., et al. (2025) Enhancing the Magnetic and Dielectric Properties of M Type Strontium Hexaferrite Nanoparticles via Aluminum Substitution: A Sol-Gel Synthesis Approach. Journal of Sol-Gel Science and Technology, 116, 421-433. https://doi.org/10.1007/s10971-025-06712-w
[46]
Rana, K., Thakur, P., Tomar, M., Gupta, V. and Thakur, A. (2018) Investigation of Cobalt Substituted M-Type Barium Ferrite Synthesized via Co-Precipitation Method for Radar Absorbing Material in Ku-Band (12-18GHz). Ceramics International, 44, 6370-6375. https://doi.org/10.1016/j.ceramint.2018.01.028
[47]
Anjum, S., Hameed, S., Awan, M.S., Amed, E. and Sattar, A. (2017) Effect of Strontium Doped M-Type Bariam Hexa-Ferrites on Structural, Magnetic and Optical Properties. Optik, 131, 977-985. https://doi.org/10.1016/j.ijleo.2016.11.205
[48]
Ijaz, M., Ullah, H., Ali Al-Asbahi, B., Ullah Khan, M., Abbas, Z. and Ullah Asif, S. (2024) Co-Precipitation Method Followed by Ultrafast Sonochemical Synthesis of Aluminium Doped M Type BaFe11.4-XAlxCo0.6O19 Hexaferrites for Various Applications. Journal of Magnetism and Magnetic Materials, 589, Article ID: 171559. https://doi.org/10.1016/j.jmmm.2023.171559
[49]
Maltoni, P., Dokala, R.K., Pramanik, P., Araujo, R., Edvinsson, T., Ivanov, S.A., et al. (2026) Temperature Dependent Magnetic and Structural Properties of Al Substituted Nanostructured Hexaferrites with Large Coercive Fields. Acta Materialia, 313, Article ID: 122273. https://doi.org/10.1016/j.actamat.2026.122273
[50]
Albanese, G., Carbucicchio, M. and Deriu, A. (1974) Temperature Dependence of the Sublattice Magnetizations in Al-and Ga-Substituted M-Type Hexagonal Ferrites. Physica Status Solidi (a), 23, 351-358. https://doi.org/10.1002/pssa.2210230202
[51]
Kumar, S., Supriya, S., Pradhan, L.K., Pandey, R. and Kar, M. (2018) Simultaneous Effect of Crystal Lattice and Non Magnetic Substitution on Magnetic Properties of Barium Hexaferrite. AIP Conference Proceedings, 1953, 1-4. https://doi.org/10.1063/1.5033105
[52]
Kittel, C. (1957) Introduction to Solid State Physics. Wiley.
[53]
Atkare, S.S., Alone, S.T., Fulari, A.V., Dhage, V.N., Kadam, R.H., Shirsath, S.E., et al. (2025) Design of Multifunctional Rare Earth Dy-Ce Substituted BaFe12O19 Nanoparticles for X-Band Microwave Absorption and EMI Shielding. Inorganic Chemistry Communications, 179, Article ID: 114805. https://doi.org/10.1016/j.inoche.2025.114805
[54]
Micheli, D. (2012) Radar Absorbing Materials and Microwave Shielding Structures Design. LAP Lambert Academic Publishing.
[55]
Li, M., Cao, X., Zheng, S. and Qi, S. (2017) Ternary Composites RgO/MoS2@Fe3O4: Synthesis and Enhanced Electromagnetic Wave Absorbing Performance. Journal of Materials Science: Materials in Electronics, 28, 16802-16812. https://doi.org/10.1007/s10854-017-7595-x
[56]
Wang, C., Hu, S., Han, X., Huang, W. and Tian, L. (2013) Controlled Synthesis and Microwave Absorption Property of Chain-Like Co Flower. PLOS ONE, 8, e55928. https://doi.org/10.1371/journal.pone.0055928
[57]
Wang, G., Ma, Z., Zheng, Y., Cheng, L., Xing, H. and Li, Z. (2024) Effect of Rare-Earth Ytterbium Doping on the Microwave Absorption Performance of Nickel-Cobalt Ferrite. RSC Advances, 14, 38345-38352. https://doi.org/10.1039/d4ra06136e
[58]
Singh, V., Rohit, Deepika, Batoo, K.M. and Singh, M. (2025) Lithium-Zinc Ferrite-Based Chitosan/Graphene Oxide Nanocomposite: An Efficient Microwave Absorbing Material for C and X Bands. Composites Communications, 56, Article ID: 102383. https://doi.org/10.1016/j.coco.2025.102383
[59]
Bai, M., Zhao, D., Zhang, Q., Wang, B. and Zhang, Y. (2026) Advances in Structural Design and High-Temperature Resistance of Electromagnetic Absorbing Materials: A Comprehensive Review. Composites Part A: Applied Science and Manufacturing, 202, Article ID: 109464. https://doi.org/10.1016/j.compositesa.2025.109464
[60]
Zia, T.U.H., Gul, I.H., Kebaili, I., Alomayrah, N., Ara, B. and Gul, K. (2025) Cole-Cole Plot Analysis of Complex Permittivity for Investigating the Dielectric Relaxation Process in Polystyrene Based High-K Nanocomposite. Materials Chemistry and Physics, 343, Article ID: 131048. https://doi.org/10.1016/j.matchemphys.2025.131048
[61]
Bao, S., Zhang, M., Jiang, Z., Xie, Z. and Zheng, L. (2023) Advances in Microwave Absorbing Materials with Broad-Bandwidth Response. Nano Research, 16, 11054-11083. https://doi.org/10.1007/s12274-023-5654-6
[62]
Chen, W., Han, M. and Deng, L. (2010) High Frequency Microwave Absorbing Properties of Cobalt Nanowires with Transverse Magnetocrystalline Anisotropy. Physica B: Condensed Matter, 405, 1484-1488. https://doi.org/10.1016/j.physb.2009.12.026
[63]
Sani, Y., Azis, R.S., Ismail, I., Yaakob, Y. and Mohammed, J. (2023) Enhanced Electromagnetic Microwave Absorbing Performance of Carbon Nanostructures for Rams: A Review. Applied Surface Science Advances, 18, Article ID: 100455. https://doi.org/10.1016/j.apsadv.2023.100455
[64]
Elmahaishi, M.F., Azis, R.S., Ismail, I. and Muhammad, F.D. (2022) A Review on Electromagnetic Microwave Absorption Properties: Their Materials and Performance. Journal of Materials Research and Technology, 20, 2188-2220. https://doi.org/10.1016/j.jmrt.2022.07.140
[65]
Zuo, D., Jia, Y., Xu, J. and Fu, J. (2023) High-Performance Microwave Absorption Materials: Theory, Fabrication, and Functionalization. Industrial & Engineering Chemistry Research, 62, 14791-14817. https://doi.org/10.1021/acs.iecr.3c02150
[66]
Li, W., Li, C., Lin, L., Wang, Y. and Zhang, J. (2019) All-Dielectric Radar Absorbing Array Metamaterial Based on Silicon Carbide/Carbon Foam Material. Journal of Alloys and Compounds, 781, 883-891. https://doi.org/10.1016/j.jallcom.2018.12.010
[67]
Zhao, B., Zhao, W., Shao, G., Fan, B. and Zhang, R. (2015) Morphology-Control Synthesis of a Core-Shell Structured Nicu Alloy with Tunable Electromagnetic-Wave Absorption Capabilities. ACS Applied Materials & Interfaces, 7, 12951-12960. https://doi.org/10.1021/acsami.5b02716
