标题：Defect-Induced Ferromagnetism in VO2(B) Nanobelts: Theoretical and Experimental Insights
作者：Guo, Donglin; Hu, Chenguo; Zhao, Zhenhuan; Xi, Yi; Liu, Hong
作者机构：[Guo, Donglin; Hu, Chenguo; Xi, Yi] Chongqing Univ, Dept Appl Phys, Chongqing 400044, Peoples R China.; [Zhao, Zhenhuan; Liu, Hong] Shandong Univ, S 更多
通讯作者地址：[Hu, CG]Chongqing Univ, Dept Appl Phys, Chongqing 400044, Peoples R China.
来源：SCIENCE OF ADVANCED MATERIALS
关键词：Vanadium Dioxide (B) Nanobelts; Ferromagnetism; Oxygen Vacancy; Density; Functional Theory
摘要：The magnetic properties of the monoclinic B phase vanadium dioxide (VO2(B)) nanobelts synthesized by the hydrothermal method are investigated. The VO2(B) nanobelts show ferromagnetism at room temperature, which disagrees with previous literatures. Oxygen vacancies and vanadium cations V3+ are found in the sample. The magnetic susceptibility is observed inversely in low and high temperature. The plots of susceptibility versus temperature can be linearly fitted according to Curie-Weiss law chi(T) = chi(o) + C/(T-theta) in temperature range of 280-320 K and 80-190 K, from which Curie point theta is obtained to be 295 K and 210 K, indicating the ferromagnetic exchange interaction in 280-320 K and antiferromagnetic exchange interaction in 80-190 K, respectively. The excessive oxygen vacancies induce the unexpected ferromagnetic nature of VO2(B) nanobelts, which is attributed to the fact that the Bader charge of V atom changes from +2.4872 to +1.834 (V+4 to V+3) based on the calculations by using density functional theory (DFT).