Controlling of Particle Size to Maximize the Coercivity of SmCo5 Hard Magnet

Research output: Contribution to conferencePosterResearch

Rare-earth magnets have been widely used for magnetic, electronic, energy applications in the world. Among these strong magnetic matierials, SmCo5 rare-earth hard magnet has the largest anisotropy field, while the coercivity of a magnet is usually less than 30% of its anisotropy field.[1] The coercivity is enhanced, when the grain size (spherical shape) is in the stable single-domain (SSD) range. Theoretical calculation predicts the SSD range of SmCo5 to be 740-870 nm,[2] however, at present, there has been no experimental data supporting the claim. Herein, we used an improved chemical method to synthesize SmCo5 particles with an average particle size (APS) range from 202 nm to 810 nm by tuning the reaction condition of the precursor, named T1, T3, T5, T8, T12, T16 based on reaction time (see Figure 1a). We found that the morphology and composition of the precursor play a significant role in determining the phase composition and APS of the final product. The maximum coercivity of 2632 kA m-1 (33.1 kOe) was obtained when the APS reached 805 nm (Figure 1b). SEM images and recoil loops demonstrate that samples with high coercivity are uniform and the coherent rotation happens during the demagnetization process. Henkel plots and δM plots verify the existing of strong exchange coupling interaction between particles, resulting in the high Mr/Ms ratios. This is the first report on optimizing the coercivity of SmCo5 based on single domain theory and the optimized APS fits very well the predicted SSD range.
Original languageEnglish
Publication year28 Aug 2019
Number of pages1
Publication statusPublished - 28 Aug 2019
EventJoint European Magnetic Symposia 2019 - Uppsala Konsert & Kongress, Uppsala, Sweden
Duration: 26 Sep 201930 Sep 2019


ConferenceJoint European Magnetic Symposia 2019
LocationUppsala Konsert & Kongress
Internet address

    Research areas

  • SmCo5 particles, high coercivity, single-domain size, chemical method

See relations at Aarhus University Citationformats

ID: 164237753