Effect of praseodymium valence change on the structure, magnetic, and microwave absorbing properties of M-type strontium ferrite: the mechanism of influence of citric acid dosage and calcination temperature

Enhanced X and Ku band microwave absorption powered by a magnetic–dielectric synergistic effect in Pr-doped M/W composite hexaferrites

“…29–32 In addition, a large number of small equiaxed Pr x Sr 1− x FeO 3− y phase grains can be observed, which leads to more heterogeneous interfaces in the sample, and may enhance interface polarization. 9,10 As shown in Fig. 3(d), the shape of W-phase grains becomes irregular after Pr doping, which may be due to lattice distortion caused by Pr in the lattice.…”

“…Guo et al 8 have synthesized Ba 0.9 RE 0.1 Co 2 Fe 16 O 27 (RE = La, Nd, and Sm) particles and studied the effect of rare earth ions on the complex permittivity and complex permeability in the range from 0.50 to 18.00 GHz. In our previous works, 9,10 we synthesized SrFe 12Àx Pr x O 19 (x = 0-0.5) and Sr x Fe 12Ày Pr 0.4 O 19Ày (x = 0.6-1.3; y = 0-0.4) powders and significantly increased the dielectric loss of strontium ferrite via Pr doping and sintering condition design. According to these studies, we found that for M-type or Wtype hexaferrites, it is difficult to achieve the simultaneous enhancement of dielectric loss and magnetic loss and obtain good impedance matching only by doping one or several ions.…”

“…For this part, please refer to our previous reports. 9,10 According to the composition of these powders, they are called M-type auto-combustion powder and W-type auto-combustion powder. Firstly, M-type auto-combustion powder is sintered at 1200 1C for 3 h, forming SrPr 0.5 Fe 11.5 O 19 hexaferrite.…”

High-Performance Microwave Absorption Materials: Theory, Fabrication, and Functionalization

“…In this system, although the Hc and lattice strain increased with increasing Nd 3+ concentration, the best RL min was only −17.72 dB and the EAB was narrow. In addition to doping with rare earth elements, ferrite could also be doped with transition metal ions, which could improve the saturated magnetization and magnetic properties of the ferrite. For instance, Cho prepared BaCo 2‑ x Me x Fe 16 O 27 (Me = Zn, Ni), and the samples doped with Zn or Ni had higher saturation magnetization than the undoped samples …”