Lake shore 7400

Synthesis and detailed morphological and structural characterization of Zn_0.25Co_0.75Fe₂O₄ (ZCFO) nanoparticles are given in refs. [41 (link),42 (link)]. The same nanoparticles for this work were prepared by the sol-gel self-combustion method [43 (link)]. The crystallite size estimated from XRD was 16 ± 2 nm. The magnetization curve was measured with a Lake Shore 7400 (Lake Shore Cryotronics, Inc., Westerville, OH, USA) vibrating sample magnetometer (VSM) on a dry powder at 297 K. The M(H) curve is loop-shaped with saturation magnetization of 74 ± 2 emu/g, M_R/M_S of 0.34 and coercivity of 540 ± 20 Oe [41 (link),42 (link)]; here, M_R stands for remanence.
BaTiO₃ (BTO) particles were prepared by the solid-state reaction method followed by a two-stage sintering: at T₁ = 1150 °C during τ₁ = 4 h (1st stage) and at T₂ = 1170 °C during τ₂ = 4 h (2nd stage). For this procedure, BaCO₃ and TiO₂ powders with purity of at least 99.95% were used as precursors. The fabrication method is in line with the conventional ceramic technology, described in detail elsewhere [44 (link)]. The resulting powder has reference size of 3 ± 1 µm. After synthesis the particles were polarized in the DC electric field E = 20 kV/cm.

The main functional groups of the samples were examined by FT-IR with a Nicolet 6700 FT-IR instrument (Thermo Fisher Scientific Inc., Waltham, MA, USA). The surface morphology of the nanoparticles was observed by scanning electron microscopy (JSM-5800, JEOL Ltd., Toyoshima, Tokyo, Japan). The elemental content of the nanoparticles was examined with an energy dispersive spectrometer (JEOL Ltd., Toyoshima, Tokyo, Japan). The size of the synthesized nanoparticles was measured by a Malvern laser particle size analyzer (ZS90, Malvern Panalytical, Malvern, UK). The crystal structure of the synthesized samples was measured by X-ray diffractometer (XRD, PANalytical B.V., Almelo, The Netherlands). The magnetizing ability of the samples was evaluated through a vibrating sample magnetometer (Lake Shore 7400, Lake Shore Cryotronics Inc., Westerville, OH, USA).