Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

In this work, an experiment was carried out to investigate the preparation condition of anisotropic, Fe-deficient, M-type Sr ferrite with optimum magnetic and physical properties by changing experimental parameters, such as the La substitution amount and little additive modification during fine milling process. The compositions of the calcined ferrites were chosen according to the stoichiometry LaxSr1-xFe12-2xO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.30. The effect of CaCO3, SiO2, and Co3O4 inter-additives on the Sr ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of Br = 4608 Gauss, bHc = 3650 Oe, iHc = 3765 Oe, and (BH)max = 5.23 MGOe were obtained for Sr ferrite hard magnets with low cobalt content at 1.7 wt%, which will eventually be used as high-end permanent magnets for the high-efficiency motor application in automobiles with Br > 4600 ± 50 G and iHc > 3600 ± 50 Oe.

Optically controlled large-coercivity room-temperature thin-film magnets

Photo-controlled room-temperature hard magnets could open new horizons for high-density information storage. For this, the material should be fabricated as device-integrable (conformal, stretchable, transparent, etc.) thin films and preferably from...

Rare-earth-free magnetically hard ferrous materials

Iron-based rare-earth-free hard magnets achieved by the combination of iron and another element.

Two-dimensional ferromagnetism in CrTe flakes down to atomically thin layers

Two-dimensional ferromagnet, chromium tellurium (CrTe) was successfully synthesized. The thickness-Curie temperature phase diagram has been obtained and the results demonstrate that CrTe flakes are good hard magnets with the thickness down to 11 nm.