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<p>This study presents a comprehensive investigation of the CoFe<sub>2</sub>O<sub>4</sub>–Pb<sub>2</sub>ScNbO<sub>6</sub> (0.5CFO–0.5PSN) composite, synthesized via a solid-state reaction method. The composite, comprising a ferrite spinel and a relaxor ferroelectric, was characterized using a suite of techniques including dielectric spectroscopy, optical analysis, X-ray diffractometry, magnetometry, magnetodielectric measurements and electrocatalytic testing. At room temperature, the real part of the complex permittivity (<i>ε′</i>) attains a value of 10<sup>5</sup>. Within the temperature range of 100–250&#xa0;°C, <i>ε′</i> increases significantly to approximately 1.4 × 10<sup>6</sup>. The temperature dependence of permittivity, <i>ε′</i>(<i>T</i>), exhibits a relaxor behaviour, which is attributed to the diffuse phase transition inherent to the PSN component and contributions from Maxwell–Wagner interfacial polarization. A distinct anomaly in the <i>ε′</i>(<i>T</i>) curve is observed near 450&#xa0;°C, manifested as a kink followed by a sharp increase. This feature is associated with the transition of the CFO component from a ferrimagnetic to a paramagnetic state. The analysis of the magnetoresistance coefficient, <i>MR</i>(<i>H</i>), reveals that the composite exhibits colossal magnetoresistance (CMR) on the order of ~ 530%. The magnitude and sign of the CMR are found to be dependent on the frequency of the applied measuring field. Key magnetic parameters were determined for both the pristine CFO and the 0.5CFO–0.5PSN composite. The comparative analysis indicates that the composite possesses reduced magnetic characteristics relative to the unmodified CFO, specifically a lower coercive field (<i>H</i><sub><i>c</i></sub> = 1037 Oe), saturation magnetization (<i>M</i><sub><i>s</i></sub> = 60.36&#xa0;emu/g), local magnetic anisotropy field (<i>H</i><sub><i>a</i></sub> = 11,208 Oe) and effective anisotropy constant (<i>K</i><sub>eff</sub> = 1.78 × 10<sup>6</sup> erg/cm<sup>3</sup>). The Tafel slopes for the CFO and the 0.5CFO–0.5PSN composite were determined to be 119&#xa0;mV/dec and 96&#xa0;mV/dec, respectively. The lower Tafel slope of the composite signifies enhanced electrocatalytic kinetics and superior electrocatalytic activity.</p>

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Structure, electrophysical, magnetic and electrocatalytic properties of the CoFe2O4–Pb2ScNbO6 composite

  • 期刊论文

  • 发表日期：

    2026年4月24日

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  • Kamaludin Abdulvakhidov,
  • Muslim Dudurgov,
  • Bashir Kulbuzhev,
  • Bashir Abdulvakhidov,
  • Salim Otajonov,
  • Nurzod Yunusov,
  • Alexander Nazarenko,
  • Ivan Dmitrenko,
  • Alexander Soldatov,
  • Pavel Plyaka,
  • Marina Sirota,
  • Suleiman Kallaev,
  • Dmitry Kim,
  • Leonid Korotkov,
  • Lubov Guda

摘要

This study presents a comprehensive investigation of the CoFe2O4–Pb2ScNbO6 (0.5CFO–0.5PSN) composite, synthesized via a solid-state reaction method. The composite, comprising a ferrite spinel and a relaxor ferroelectric, was characterized using a suite of techniques including dielectric spectroscopy, optical analysis, X-ray diffractometry, magnetometry, magnetodielectric measurements and electrocatalytic testing. At room temperature, the real part of the complex permittivity (ε′) attains a value of 105. Within the temperature range of 100–250 °C, ε′ increases significantly to approximately 1.4 × 106. The temperature dependence of permittivity, ε′(T), exhibits a relaxor behaviour, which is attributed to the diffuse phase transition inherent to the PSN component and contributions from Maxwell–Wagner interfacial polarization. A distinct anomaly in the ε′(T) curve is observed near 450 °C, manifested as a kink followed by a sharp increase. This feature is associated with the transition of the CFO component from a ferrimagnetic to a paramagnetic state. The analysis of the magnetoresistance coefficient, MR(H), reveals that the composite exhibits colossal magnetoresistance (CMR) on the order of ~ 530%. The magnitude and sign of the CMR are found to be dependent on the frequency of the applied measuring field. Key magnetic parameters were determined for both the pristine CFO and the 0.5CFO–0.5PSN composite. The comparative analysis indicates that the composite possesses reduced magnetic characteristics relative to the unmodified CFO, specifically a lower coercive field (Hc = 1037 Oe), saturation magnetization (Ms = 60.36 emu/g), local magnetic anisotropy field (Ha = 11,208 Oe) and effective anisotropy constant (Keff = 1.78 × 106 erg/cm3). The Tafel slopes for the CFO and the 0.5CFO–0.5PSN composite were determined to be 119 mV/dec and 96 mV/dec, respectively. The lower Tafel slope of the composite signifies enhanced electrocatalytic kinetics and superior electrocatalytic activity.