Data supporting the results of the characterization of the phases and structures appearing during the synthesis process of Ba0.5Sr1.5Zn2-xNixFe12O22 by auto-combustion.

The data presented has to do with identifying the various phases arising during the synthesis of the Y-type hexaferrite series Ba0.5Sr1.5Zn2-xNixFe12O22 by auto-combustion that we deem important for their microstructural and magnetic properties. The data and the related analyses support the research paper "Ni-substitution effect on the properties of Ba0.5Sr1.5Zn2-xNixFe12O22 powders" [1]. Thus, the parameters are presented of the phases appearing after auto-combustion and after the initial annealing at 800 °C, namely, crystal cell and crystallite size. Also, additional data are provided obtained by EDS concerning the Ba:Sr:Zn:Ni:Fe ratio in Ba0.5Sr1.5Zn2-xNixFe12O22 (x = 0.8, 1, 1.5) samples synthesized at 1170 °C for 10 h. The data can be used as a reference in establishing how the phases distinguished during the initial process of auto-combustion affect the Ba0.5Sr1.5Zn2-xNixFe12O22 powders, which are candidates for room-temperature multiferroic materials. The data have not been published previously and are made available to permit critical or further analyses.

Specifications Table

Value of the Data

The data distinguishes the intermediate phases appearing during the synthesis of a Y-type hexaferrite (Ba0.5Sr1.5Zn2-xNixFe12O22) by auto-combustion;

The EDS analysis yields reliable information on the chemical composition at different points on bulk Ba0.5Sr1.5Zn2-xNixFe12O22 samples;

The data could be useful in identifying the phases and their effect during the synthesis of other hexaferrites;

The data supplies important additional information to the related research article.

Data description

The data and analyses included here corroborate the results of and the conclusions drawn from the study of Ba0.5Sr1.5Zn2-xNixFe12O22 (x = 0.8, 1, and 1.5) hexaferrites synthesized by sol-gel auto-combustion [1]. The XRD analysis was employed to distinguish between the phases formed during the consecutive steps of the synthesis of Ba0.5Sr1.5Zn2-xNixFe12O22 (x = 0.8, 1, and 1.5). Fig. 1 shows the XRD patterns of the auto-combusted powders and the powder treated at 800 °С for three hours for samples with x = 1, and 1.5. The corresponding XRD patterns for sample Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22 are presented in Koutzarova et al. [1]. A spinel-type phase (Ni-Zn mixed ferrite (Zn, Ni)Fe2O4) and (Ba, Sr)CO3 were observed in the as-synthesized auto-combustion powders. The XRD-patterns of the powders heat-treated at 800 °С exhibit the peaks of spinel type phase BaFeO3-x and BaSrFe4O8. Table 1 summarizes the data for the crystal cell parameters, the average crystallite size and the phases’ percentage content derived from the XRD patterns. The original output files for all three samples (x = 0.8, 1, and 1.5) obtained by Topas 4.2 are given in the supplementary file.

Fig. 1

XRD-patterns of auto-combusted powders (a, c) and powder annealed at 800 °С for three hours (b, d) for samples x = 1 (a, b), and 1.5 (c, d).

Table 1

Phase percentage, crystal cell parameters and average crystallite size obtained from the XRD patterns of auto-combusted powders and powder annealed at 800 °С for three hours.

Sample	Spinel	(Ba,Sr)CO3	(Ba,Sr)FeO3-x	BaSrFe4O8
Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22auto-combusted powderpercentageabccrystallite size	87%8.378(6) Å10 nm	13%5.099(4) Å8.624(9) Å6.098(4) Å19 nm
Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22annealed at 800°Сpercentageabccrystallite size	65%8.395(5) Å11 nm		25%5.664(1) Å21.681(4) Å5 nm (fix)	10%5.435(5) Å8.055(5) Å79 nm
Ba0.5Sr1.5ZnNiFe12O22auto-combusted powderpercentageabccrystallite size	87%8.371(1) Å11 nm	13%5.098(2) Å8.621(8) Å6.105(5) Å19 nm
Ba0.5Sr1.5ZnNiFe12O22annealed at 800°Сpercentageabccrystallite size	68%8.385(1) Å12 nm		27%5.685(4) Å21.860(3) Å5 nm (fix)	5%5.446(2) Å8.071(6) Å24 nm
Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22auto-combusted powderpercentageabccrystallite size	88%8.357(8) Å9 nm	12%5.101(0) Å8.601(6) Å6.097(6) Å21 nm
Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22annealed at 800°Сpercentageabccrystallite size	67%8.368(1) Å10 nm		27%5.659(0) Å21.740(4) Å5 nm (fix)	6%5.437(0) Å8.052(9) Å79 nm

Fig. 2 displays XRD-patterns in the 2-theta range 37.3° – 45.3° of Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22, Ba0.5Sr1.5ZnNiFe12O22 and Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22 treated at 1170 °C. No signs were observed of nickel spinel ferrite decomposition to NiO during the Y-type hexaferrite formation process [2].

Fig. 2

XRD-patterns of (a) Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22, (b) Ba0.5Sr1.5ZnNiFe12O22 and (c) Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22 in the 2-theta range 37.3° – 45.3°. The expected peak positions of NiO (PDF number 00–047–1049) are marked in red.

The statistical data yielded by the analysis of the four points of EDX spectrum of polished cross-sections of the bulk samples of Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22, Ba0.5Sr1.5ZnNiFe12O22 and Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22 are given in Table 2.

Table 2

The Ba:Sr:Zn:Ni:Fe ratio estimated from the EDX analyses of Ba0.5Sr1.5Zn2-xNixFe12O22 (x = 0.8, 1, 1.5) samples at the four points on polished cross-sections surface.

Sample	Ba0.5Sr1.5Zn1.2Ni0.8Fe12O22	Ba0.5Sr1.5ZnNiFe12O22	Ba0.5Sr1.5Zn0.5Ni1.5Fe12O22
	Ba:Sr:Zn:Ni:Fe	Ba:Sr:Zn:Ni:Fe	Ba:Sr:Zn:Ni:Fe
Point 1	0.5:1.5:1.1:0.8:12.3	0.5:1.7:1.7:1.7:16.7	0.5:1.5:0.5:1.4:12.9
Point 2	0.5:1.6:1.2:0.7:12.4	0.5:1.5:1.8:1.5:16.6	0.5:1.5:0.5:1.3:12.0
Point 3	0.5:1.5:1.1:0.8:12.4	0.5:1.7:1.1:1.0:12.3	0.5:1.7:0.5:1.3:12.6
Point 4	0.5:1.5:1.0:0.8:12.2	0.5:1.6:2.2:2.2:15.1	0.5:1.6:0.6:1.4:12.9

Experimental design, materials, and methods

Polycrystalline samples of Ba0.5Sr1.5Zn2-xNixFe12O22 (x = 0.8, 1, and 1.5) were fabricated by a modified citric acid sol-gel auto-combustion using stoichiometric amounts of the precursors; a detailed description of the sample preparation methodology is given in [1]. In brief, the powders produced after the auto-combustion process were annealed at 800 °С for three hours. All powders were subjected to homogenization by vibrating ball milling; then the resulting powders were pressed at 7 MPa to bulk pellets with a diameter of 16 mm. The pellets were heat-treated at 1170 °С in air for 10 h to obtain the Ba0.5Sr1.5Zn2-xNixFe12O22 compositions with x = 0.8, 1, and 1.5. Subsequently, the bulk pellets were cut and polished for microscopic studies.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.

Subject	Materials Science, Electronic, Optical and Magnetic Materials
Specific subject area	Multiferroic Materials, Hexaferrites, Sol-Gel Auto-Combustion
Type of data	TablesFiguresText file
How data were acquired	X-ray diffraction (XRD) measurements performed using a Brucker D8 diffractometerScanning electron microscopy and energy dispersive X-ray spectroscopy (FEI XL30 FEG-ESEM, Bruker Quantax EDS coupled to ESEM)
Data format	RawAnalyzedFiltered
Parameters for data collection	The characterization was implemented by X-ray diffraction (XRD) carried out by a Brucker D8 diffractometer (40 kV, 30 mA) controlled by DIFFRACTPLUS software in Bragg-Brentano reflection geometry with Cu-Kα radiation (λ = 1.5418 Å); and by scanning electron microscopy and energy dispersive X-ray spectroscopy (FEI XL30 FEG-ESEM, Bruker Quantax EDS coupled to ESEM).
Description of data collection	The XRD experiments were conducted on powder samples. The percentage, crystal cell parameters and crystallite size of the phases were determined from X-ray diffractograms. The EDS analyses were performed on four points on polished cross-sections of bulk samples (pellets) in view of finding the Ba:Sr:Zn:Ni:Fe ratio.
Data source location	Institution: Institute of Electronics, Bulgarian Academy of SciencesCity: SofiaCountry: BulgariaInstitution: Institute of General and Inorganic ChemistryCity: SofiaCountry: BulgariaInstitution: Greenmat, Chemistry Department, University of Liege,City: LiègeCountry: Belgium
Data accessibility	With the article
Related research article	T. Koutzarova, S. Kolev, K. Krezhov, B. Georgieva, Ch. Ghelev, D. Kovacheva, B. Vertruyen, R. Closset, L. M. Tran, M. Babij, A. J. Zaleski, Ni-substitution effect on the properties of Ba0.5Sr1.5Zn2-xNixFe12O22 powders, J. Magn. Magn. Mater. doi: 10.1016/j.jmmm.2020.166725