Article · Wikipedia archive · Last revised Jul 26, 2026

Cobalt ferrite

Cobalt ferrite is a semi-hard ferrite with the chemical formula CoFe2O4 (CoO·Fe2O3). The substance can be considered as between a soft and hard magnetic material and is usually classified as a semi-hard material.

Last revised
Jul 26, 2026
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≈ 2 min
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Source
Wikipedia ↗
Cobalt ferrite
Names
IUPAC name
cobalt(2+);iron(3+);oxygen(2-)
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • 234-992-3
  • InChI=1S/Co.2Fe.4O/q+2;2*+3;4*-2
    Key: MMOVVVBHLUGHGW-UHFFFAOYSA-N
  • [O-2].[O-2].[O-2].[O-2].[Fe+3].[Fe+3].[Co+2]
Properties
CoFe2O4
Molar mass 234.619 g·mol−1
Hazards
GHS labelling:1
GHS06: ToxicGHS08: Health hazard
Danger
H317, H330, H334, H360F, H372
P203, P233, P260, P264, P270, P271, P272, P280, P284, P302+P352, P304+P340, P316, P318, P319, P320, P321, P333+P317, P342+P316, P362+P364, P403, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cobalt ferrite is a semi-hard ferrite with the chemical formula CoFe2O4 (CoO·Fe2O3). The substance can be considered as between a soft and hard magnetic material and is usually classified as a semi-hard material.2

Uses

Cobalt ferrite is mainly used for its magnetostrictive properties in applications such as sensors and actuators3 due to its high saturation magnetostriction (~200 ppm). CoFe2O4 is not composed of rare-earth elements, making it a good substitute for Terfenol-D.4 Moreover, its magnetostrictive properties can be tuned by inducing a magnetic uniaxial anisotropy.5 This can be done by magnetic annealing,6 magnetic field assisted compaction,7 or reaction under uniaxial pressure.8 This last solution has the advantage of being ultrafast (20 min) due to the use of spark plasma sintering. The induced magnetic anisotropy in cobalt ferrite enhances the magnetoelectric effect in composite.9

It can be also used as electrocatalyst for the oxygen evolution reaction and as a material for fabricating electrodes for use in electrochemical capacitors (also named supercapacitors). These applications depend on redox reactions occurring at the ferrite surface. Cobalt ferrite can be prepared with controlled morphology and size to enhance the surface area, and thus the number of active sites.10

One disadvantage of cobalt ferrite is its low electrical conductivity. Nanostructures of different shapes can be synthesized utilizing conducting substrates, such as reduced graphene oxide, to alleviate this disadvantage.10

References

References

  1. PubChem. "Cobalt iron oxide (CoFe2O4)". pubchem.ncbi.nlm.nih.gov. Retrieved 2026-03-11.
  2. Hosni (2016). "Semi-hard magnetic properties of nanoparticles of cobalt ferrite synthesized by the co-precipitation process". Journal of Alloys and Compounds. 694: 1295–1301. doi:10.1016/j.jallcom.2016.09.252.
  3. Olabi (2008). "Design and application of magnetostrictive materials" (PDF). Materials & Design. 29 (2): 469–483. doi:10.1016/j.matdes.2006.12.016.
  4. Sato Turtelli; et al. (2014). "Co-ferrite – A material with interesting magnetic properties". IOP Conference Series: Materials Science and Engineering. 60 (1) 012020. Bibcode:2014MS&E...60a2020T. doi:10.1088/1757-899X/60/1/012020.
  5. J. C. Slonczewski (1958). "Origin of Magnetic Anisotropy in Cobalt-Substituted Magnetite". Physical Review. 110 (6): 1341–1348. Bibcode:1958PhRv..110.1341S. doi:10.1103/PhysRev.110.1341.
  6. Lo (2005). "Improvement of magnetomechanical properties of cobalt ferrite by magnetic annealing". IEEE Transactions on Magnetics. 41 (10): 3676–3678. Bibcode:2005ITM....41.3676L. doi:10.1109/TMAG.2005.854790. S2CID 45873667.
  7. Wang (2015). "Magnetostriction properties of oriented polycrystalline CoFe2O4". Journal of Magnetism and Magnetic Materials. 401: 662–666. doi:10.1016/j.jmmm.2015.10.073.
  8. Aubert, A. (2017). "Uniaxial anisotropy and enhanced magnetostriction of CoFe2O4 induced by reaction under uniaxial pressure with SPS". Journal of the European Ceramic Society. 37 (9): 3101–3105. arXiv:1803.09656. doi:10.1016/j.jeurceramsoc.2017.03.036. S2CID 118914808.
  9. Aubert, A. (2017). "Enhancement of the Magnetoelectric Effect in Multiferroic CoFe2O4/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy". IEEE Transactions on Magnetics. 53 (11): 1–5. arXiv:1803.09677. Bibcode:2017ITM....53A6162A. doi:10.1109/TMAG.2017.2696162. S2CID 25427820.
  10. Ortiz-Quiñonez, Jose-Luis; Das, Sachindranath; Pal, Umapada (October 2022). "Catalytic and pseudocapacitive energy storage performance of metal (Co, Ni, Cu and Mn) ferrite nanostructures and nanocomposites". Progress in Materials Science. 130 100995. doi:10.1016/j.pmatsci.2022.100995.