Published: 07-06-2020| Version 1 | DOI: 10.17632/68msvm9hxc.1
Jairo Roa-Rojas


XRD data, VESTA figures, SEM images, EDS and DRS spectra, E-J and resitivity curves, susceptibility and magnetization data.


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The structural characterization of the samples was carried out using a PANalytical X'pert-Pro X-ray diffractometer, applying the Bragg-Brentano configuration, with a gradual step of 0.001° in 2Theta by t=10 s, using a CuKα X-ray tube with λ=1.540598 Å. The obtained data were analyzed by means of rigorous Rietveld refinement. The surface morphological study of the samples was carried out by means of scanning electron microscopy (SEM) images taken on a TESCAN Vega 3 SB equipment with backscatter (BSE) and secondary (SE) detectors. Using an X-ray cannon microprobe (Bruker) attached to the electron microscope, a semiquantitative Energy-dispersive spectroscopy (EDS) analysis was performed to determine the composition of the samples. The electrical response was measured on 5.0 mm long, 2.0 mm wide and 1.0 mm thick rectangular samples cut with a diamond disc, on which gold electrodes were deposited. The electrical resistivity measurements were made in the temperature regime between 50 K and 425 K in a Janis Research cryogenic system (VPF-475) with temperature variation through a Lake Shore 332 controller, at a rate of 1.5 K/min. I-V characteristics at room temperature were obtained by using a Keithley-6517A DC electrometer containing a specimen holder with gold-plated silver contacts. Measurements of relative electrical permittivity as a function of frequency at room temperature were made using an Agilent - 4294A frequency analyzer. The band gap and energy excitation regimes at room temperature were examined by using a VARIAN Cary 5000 UV–Vis–NIR diffuse reflectance spectrophotometer, which has an integration sphere with a PMT/Pbs detector. Magnetic characterization took place by means of magnetic susceptibility measurements as a function of temperature (between 50 K and 320 K), following the Zero Field Cooling (ZFC) and Field Cooled (FC) recipes in an applied field of 500 Oe, thus as magnetization curves as a function of applied field intensity (-8.0 kOe < H < +8.0 kOe) at the fixed temperatures of 50, 200 and 300 K, using a VSM-VersaLab Quantum Design).