Metal-to-insulator transition and its effective manipulation studied from investigations in V1-xNbxO2 bulks. Issue 3 (15th February 2018)

• Record Type: Journal Article
• Authors: Zhang, Run; Yin, Chongyang; Fu, Qingshan; Li, Canglong; Qian, Guoyu; Chen, Xinghan; Lu, Chengliang; Yuan, Songliu; Zhao, Xiujian; Tao, Haizheng
• Is Part Of: Ceramics international. Volume 44:Issue 3(2018)
• Page Start: 2809
• Page End: 2813
• Publication Date: 2018-02-15
• Subjects: Vanadium dioxide -- Metal-insulator transition -- V-V dimers -- Ionic size effect -- Electron localization; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2017.11.024
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Nb doping effects on crystalline structure, transport transition and magnetic properties are investigated for V1- x Nb x O2 (0 ≤ x ≤ 5%) bulks. At room temperature, doping does not change structure of monoclinic phase but causes an increase in lattice parameters for the range of x ≤ 3%, further doping leads to a structure transition to rutile tetragonal phase. Each sample simultaneously displays a transition to insulating behavior and a sharp decrease in susceptibility below an almost same critical temperature ( T c ). T he T c is shown to shift from ~ 340 K at x = 0 to ~ 277 K at x = 5% at a rate of ~ −13 K/at%. It is argued that the observed sharp decrease in susceptibility originates from the formation of V-V dimers with spins in anti-parallel, while the insulating behavior below T c is due to the electron movement from one dimerized state to another with the help of Variable-Range-Hopping mechanism. Furthermore, it is proposed that doping by larger cations, which would suppress the formation of dimers, can be used to manipulate the metal-insulator transition to lower temperatures.