DOI: 10.20350/digitalcsic/9893
title: Optimization of magnetic properties in fast consolidated SrFe12O19 nanocrystallites

description: The work contains 5 figures and the datasets corresponding to each figure are included in separate folders in form of .xy format or .png format. 1) The folder “Fig1” contains the “Fig1.png” which illustrates the SPS sintering conditions regarding the heating rate, dwelling time and the applied uniaxial pressure. The lower part of the figure is an illustration of the setup used at the pre/alignment of particles in an external magnetic field up to 0.55 Tesla. 2) The folder “Fig2” contains the powder X-ray data measured for different Sr/Fe molar ratios (“SrFe1I2_data.xy”, “SrFe1I4_data.xy”, “SrFe1I6_data.xy”,” SrFe1I8_data.xy) and the calculated data based on Rietveld refinement by using FullProf (“SrFe1I2_calculated.xy”, “SrFe1I4_ calculated xy”, “SrFe1I6_ calculated.xy”,” SrFe1I8_ calculated.xy”). The .xy files contain two tab delimited columns. The first column represent the 2theta diffraction angle and the second column gives the arbitrary intensities. “Figure2.png” gives the weight percentages of the different chemical phases detected in the powders while the lower part of the figure gives the crystallites sizes calculated by FullProf program. 3) The folder “Fig3” contains the magnetization data in a form of hysteresis loops measured at room temperature. Each file contains 3 columns. First column represent the applied external magnetic field (Oe units), the second column is the emu while the third column represents the emu/grams units. 4) The folder “Fig4” contains the oriented volume fraction data. Each file is a 2 columns data. The tilting angle k is given in the first column while the oriented volume fraction is given in the second column. “Fig4.png” show the pole figures obtained from x-ray diffraction measurements. 5) The folder “Fig5” gives the data repository for hysteresis loops measured at room temperature. Here the effect of external magnetic field influence prior compaction was studied. Four data sets are included here. “H_0.15T “, “H_0.45T”, “H_0.55T” and “H_0.15T_t2min. The columns are the same as described for folder “Fig3”.
description: [EN] The magnetic properties of SrFe12O19 nanocrystallites produced by hydrothermal synthesis and consolidated by Spark Plasma Sintering (SPS) were optimized by varying the compaction parameters: sintering time, sintering temperature, uniaxial pressure or pre-compaction in a magnetic field. Highly textured compacts with a high degree of crystallite alignment were produced. Qualitative and quantitative textural information was obtained based on X-ray diffraction pole figure measurements. The optimum sintering conditions, relating the degree of alignment and bulk magnetic properties, were identified based on the resulting magnetic properties. It was found that one must strike a balance between the degree of crystallite alignment for high saturation magnetisation and coercivity (Hc) to gain the highest energy product (BHmax). It was found that the coercive field drops when the crystallite alignment increases. This was particularly pronounced in the case of magnetically pre-aligned powders prior to SPS, where Hc and BHmax decreased as the pellets became increasingly textured. The best BHmax value of 29(4) kJ m−3 was found for the sample sintered at 950 °C for 2 minutes with an applied pressure of 100 MPa for a powder pre-aligned in an applied field of 0.55 T. The results presented here show the potential of SPS consolidation of SrFe12O19 with high relative densities and emphasize the effect of the degree of alignment on the decrease of coercive field and its influence on the magnetic performance.