Investigation of structural, magnetic and dielectric properties of gallium substituted Z-type Sr3Co2-Ga Fe24O41 hexaferrites for microwave absorbers

Gallium-substituted X-type hexagonal ferrites Sr2Co2GaxFe28−xO46: effect of substitution and heating temperature on phase formation and magnetic and dielectric properties

“…With the addition of gallium the semi-circles become incomplete and a second semi-circle also emerges at low frequencies which is due to grain resistance. 58 While in the case of samples heated to 1300 °C the sample with maximum gallium shows a second semi-circle at low frequency while all others possess well-defined and complete arcs at high frequencies, which are due to grain boundary resistance. 69,70 Although not shown here, the dielectric loss of the GX16 sample is very high at low frequency, which is due to the presence of multiple phases and it being a heterogenous system.…”

Crystal structure and magneto‐dielectric properties of Co‐Zr co‐substituted Co2Z hexaferrites

“…The occupancy distribution of Fe ions in Z-type hexaferrite and the spin orientation of different sites are shown in Table 2. 13,20 Because of the difference in ionic magnetic moments and spin orientations, the overall net magnetic moment of the ferrite changes after Co 2+ and Zr 4+ enter the lattice and replace Fe 3+ . Therefore, the substitution affects the magnetic properties of the hexaferrite.…”

“…Z‐type hexaferrite consists of basic blocks (R, S, T, R*, S*, and T*) stacked along the c‐axis. In particular, Fe and Co will occupy six octahedral sites with a coordination number of 6 (12 k VI , 4 f VI , 4 e VI , 4 f VI * , 12 k VI * , and 2 a VI ), three tetrahedral sites with a coordination number of 4 (4 e IV , 4 f IV , 4 f IV * ), and one five‐fold site with a coordination number of 5 (2 d V ) 18,20 . The polyhedral structures with different coordination number are also shown in Figure 3.…”

Design and development of Ga-substituted Z-type hexaferrites for microwave absorber applications: Mössbauer, static and dynamic properties

“…The increasingly positive value of <Δ> (Fig. 8(f)) of Sr 3 Co 2-x Ga x Fe 24 O 41 hexaferrites indicates that the magnetic anisotropy is progressing towards the c-axis with Ga-substitution [42,64,75], meaning that the angle of the cone of magnetisation to the c-axis found in unsubstituted SrZ hexaferrite will probably becoming smaller, and as a result H C will also increase for Ga-substituted samples [79]. The magnetic anisotropy of Sr 3 Co 2-x Ga x-Fe 24 O 41 hexaferrites is modified from the c plane to c-axis orientation at x = 0.4-0.8.…”