Combinatorial Bulk Ceramic Magnetoelectric Composite Libraries of Strontium Hexaferrite and Barium Titanate

Abstract

Bulk ceramic combinatorial libraries were produced via a novel, high-throughput (HT) process, in the form of polycrystalline strips with a gradient composition along the length of the library. Step gradient ceramic composite libraries with 10 mol % steps of SrFe12O19-BaTiO3 (SrM-BT) were made and characterized using HT methods, as a proof of principle of the combinatorial bulk ceramic process, and sintered via HT thermal processing. It was found that the SrM-BT libraries sintered at 1175 °C had the optimum morphology and density. The compositional, electrical and magnetic properties of this library were analyzed, and it was found that the SrM and BT phases did not react and remained discrete. The combinatorial synthesis method produced a relatively linear variation in composition. The magnetization of the library followed the measured compositions very well, as did the low frequency permittivity values of most compositions in the library. However, with high SrM content of ≥80 mol %, the samples became increasingly conductive, and no reliable dielectric measurements could be made. Such conductivity would also greatly inhibit any ferroelectricity and magnetoelectric coupling with these composites with high levels of the SrM hexagonal ferrite.

Visible-Light-Driven Photocatalytic Activity of Magnetic BiOBr/SrFe12O19 Nanosheets

“…The intimate contact effect of BiOBr/SrFe 12 O 19 is analogous to a p–n heterojunction structure in the photocatalytic performance, which was absent in the single BiOBr. In addition, the conduction band (CB) and valence band (VB) potentials of the p-type semiconductor, BiOBr, were 0.30 and 3.10 eV [35,36], respectively. Meanwhile, the CB and VB of n-type SrFe 12 O 19 were 0.20 and 2.06 eV, respectively [37,38].…”

Gel Synthesis of Hexaferrites Pb1−xLaxFe12−xZnxO19 and Properties of Multiferroic Composite Ceramics PZT–Pb1−xLaxFe12−xZnxO19

“…In the literature, there is a lot of data about biphasic multiferroic systems based on hexaferrites of strontium [ 14 , 15 ] and barium [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], as well as solid solutions based on BaFe 12 O 19 (BaFe 12− x Mn x O 19 [ 23 ], BaFe 11.9 Al 0.1 O 19 [ 24 ]), where barium titanate [ 14 , 15 , 16 , 20 , 21 , 22 , 23 , 24 ], strontium barium titanate [ 19 ], bismuth sodium titanate [ 18 , 21 , 22 ], and potassium–sodium niobate [ 17 ] are used as piezoelectric components. The authors of most of the above mentioned papers note the absence of extraneous phases in the composites after firing, although the composites described by Want et al [ 20 ] and by Trukhanov et al [ 24 ] contain impurity phases with a spinel structure.…”

“…With an increase in the ferrite content, there is a regular decrease in the dielectric permittivity, remanent electric polarization, and coercive force, and an increase in the remanent magnetization as described by Rather et al [ 14 ], Pular et el. [ 15 ], Kumar et al [ 17 ], and by Pattanayak et al [ 18 ]. We can also see the dependence of these parameters on the phase particle sizes in the content of the composites [ 24 ].…”

“…We can also see the dependence of these parameters on the phase particle sizes in the content of the composites [ 24 ]. Depending on their compositions, the electrical properties of the composites often change nonlinearly; apparently, there are percolation effects [ 15 , 18 ]. Gao et al [ 23 ] have shown that barium hexaferrite doping with manganese cations provides an increase in the resistivity of composite ceramics and a decrease in the dielectric loss tangent.…”

Monolithic Magneto-Optical Nanocomposites of Barium Hexaferrite Platelets in PMMA

“…Barium hexaferrite, with a basic composition of BaFe 12 O 19 , is one of the most commonly used materials in hard-magnetic, magnetic recording and high-frequency applications56. However, novel applications for barium hexaferrite have been found in multifunctional (nano)composites, i.e., magnetic photocatalysis, magneto-optics, magneto-electrics, magnetic gels, and ferromagnetic fluids789101112. Magnetic materials, in general, can be exploited in magneto-optical (MO) applications, such as recording, sensors and switches, imaging and in a variety of other optical components, like isolators, circulators and modulators13141516.…”