Enhancement of magnetic properties in Mn–Zn substituted M-type Sr-hexaferrites

We report the magnetic properties of Mn–Zn substituted M-type Sr-hexaferrites (SrM), SrFe12−2xMnxZnxO19, and compare them with those of non-substituted SrM and La–Zn substituted SrM. The highest saturation magnetization (MS) of 75.6emu/g was obtained at a Mn–Zn substitution of x=0.1 (SrFe11.8Mn0.1Zn0.1O19), which is higher than those of the non-substituted SrM and La–Zn substituted SrM by 2.6% and 1.7%, respectively. The enhanced MS can be attributed to the selective substitution of Zn2+ and Mn4+ into the down-spin site of Fe3+ (4f1 or 4f2). Sintered anisotropic magnets fabricated with the optimal Mn−Zn doping level of x=0.1 exhibited a remanent magnetic induction (Br) over 4300G and maximum energy product (BH)max of ~4.6MGOe (36.6kJ/m3). •The magnetic properties of Mn–Zn SrM were compared with those of non-substituted SrM and La–Zn SrM.•The highest MS of 75.6emu/g was obtained at the Mn–Zn substitution x=0.1 (SrFe11.8Mn0.1Zn0.1O19).•Sintered anisotropic Mn–Zn SrM magnets showed values of Br over 4300G and (BH)max of ~4.6MGOe (36.6kJ/m3).