Investigation of the influence of VO₂ formation on the structural morphology and magnetic properties in hydrothermally synthesized V₆O₁₃

Investigating the impact of hydrothermal duration on electronic magnetism, two distinct samples were synthesized: the V₆O₁₃ phase (S1) with 0.5 h of hydrothermal reaction, and the V₆O₁₃ and VO₂ coexistent phase (S2) with 6 h of reaction. X-ray diffraction identified S1 as monoclinic C2/m, and S2 with a 4:1 ratio of V₆O₁₃ in P21/c space group VO₂. Electron microscopy revealed rod-like V₆O₁₃ and spherical VO₂. Both samples exhibited metal-insulator transitions, with the presence of VO₂ in S2 elevating the metal-insulator phase transition onset temperature and widening the transition range. S1 exhibits antiferromagnetic ordering at low temperatures (T_N ~ 55 K) and follows the Curie-Weiss law above the metal-insulator transition temperature, while the behavior of S2 was modeled by a combination of Pauli and Curie-like paramagnetism, aligning well with experimental data. Small hysteresis loops in both samples suggested weak ferromagnetism; the linear loop of S1 indicated strong vanadium electron correlation, and the incomplete S-loop of S2 was attributed to the influence of VO₂ on the electronic magnetism of V₆O₁₃.