Theoretical study of the influence of vacancies in the magnetic stability of V-, Cr-, and Mn-doped SnO2

• Published in: Applied surface science 2013-02, Vol.267, p.115-118
• Main Authors: Borges, Pablo D., Scolfaro, Luisa M.R., Leite Alves, Horácio W., da Silva, Eronides F., Assali, Lucy V.C.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dilute magnetic semiconductor; Exact sciences and technology; Magnetic metastability; Physics; Spin-crossover; Spintronics; Tin dioxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.08.096

► Oxygen vacancies play an important change in magnetic stability of V-, Cr-, and Mn-doped SnO2. ► High spin (HS) ground state and low spin (LS) were observed for these systems. ► The spin crossover energies from the LS to the HS where calculated. ► Our findings suggest that these materials may be used in applications that require different magnetization states. In this work we study, theoretically, the magnetic properties of transition metals (TMs)-doped SnO2 (with TM=V, Cr, and Mn) in a diluted magnetic oxide configuration, focusing in particular in the role played by the presence of O vacancies, VO, nearby the TM. We present the results of first-principles electronic structure calculations of Sn0.96TM0.04O2 and Sn0.96TM0.04O1.98(VO)0.02 alloys. The calculated total energy as a function of the total magnetic moment per cell shows a magnetic metastability, corresponding to a high-spin (HS) ground state, respectively, with 2 and 3μB/cell, for Cr and Mn, and a metastable low-spin (LS) state, with 0 (Cr) and 1 (Mn)μB/cell. For vanadium, only a state with 1μB/cell was found. The spin-crossover energy (ESCO) from the LS to the HS is 114meV for Cr and 42meV for Mn. By creating O vacancies close to the TM site, we show that the metastability and ESCO change. For chromium, a new HS state appears (4μB/cell), with an energy barrier of 32meV relative to the 2μB/cell state. For manganese, the metastable LS state of 1μB/cell disappears, while for vanadium the HS state of 1μB/cell remains. In all cases, the ground state corresponds to the expected HS. These findings suggest that these materials may be used in applications that require different magnetization states.