Exploring the magnetic properties and magnetic coupling in SrFe12O19/Co1-xZnxFe2O4 nanocomposites

Combined characterization approaches to investigate magnetostructural effects in exchange-spring ferrite nanocomposite magnets

“…Recently, Maltoni et al proposed a one-pot synthesis to produce exchange-spring ferrite nanocomposites where both the hexaferrite SrFe 12 O 19 and spinel Zn x Co 1− x Fe 2 O 4 phases could be formed in the same reaction container. 33 Despite the differences in the synthesis processes, the exchange-spring nanocomposites investigated by Maltoni et al had similar magnetic properties with values of M S , M R and H C quite comparable to the core-coat NC presented here.…”

“…Prior studies have emphasized the importance of close contact between the hard and soft phases for obtaining well coupled exchange-spring magnets. 22,24,33,64 Individual particles of separate phases in a physically mixed composite are quite likely to lack intimate surface contact and therefore, are expected to be magnetically uncoupled. Compared to the parent SrFe 12 O 19 NPs, the powder-blend NC exhibits an increase in the M S and M R values (while retaining the M R /M S ratio).…”

“…24,[26][27][28] Oxide-based exchange-spring magnets are attractive alternatives due to the low cost and high corrosion resistance along with relative tolerance of magnetic performance to defects. 19,20,[29][30][31][32][33] Magnetic ferrites are widely used magnets, where hexaferrites presents a high H C material (B500 kA m À1 ), while spinel ferrites are attributed with high M S (B90 Am 2 kg À1 ). 16,19,20,34,35 The magnetoplumbite strontium hexaferrite (SrFe 12 O 19 ; space group: P6 3 /mmc) is formed of a hexagonally packed lattice of oxygen ions with every 5th layer having one oxygen ion replaced by a strontium ion.…”

Chemical engineering of cationic distribution in spinel ferrite nanoparticles: the effect on the magnetic properties

“…For these reasons, spinel ferrite nanoparticles (NPs) are suitable for many applications such as MRI contrast agents, [1][2][3] molecular detection and separation, drug delivery systems and hyperthermic therapy, 4,5 and design of rare-earth-free permanent magnets. [6][7][8][9][10][11] The spinel ferrite structure consists of a cubic close-packed (ccp) arrangement of oxygen atoms with tetrahedral (T d ) and octahedral [O h ] sites. [12][13][14] The cationic distribution is often reported as (M 1Àd 2+ Fe d…”

“…For these reasons, spinel ferrite nanoparticles (NPs) are suitable for many applications such as MRI contrast agents, 1–3 molecular detection and separation, drug delivery systems and hyperthermic therapy, 4,5 and design of rare-earth-free permanent magnets. 6–11…”