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

Abstract In this work we study, theoretically, the magnetic properties of transition metals (TMs)-doped SnO 2 (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, V O , nearby the TM. We present the results of first-principles electronic structure calculations of Sn 0.96 TM 0.04 O 2 and Sn 0.96 TM 0.04 O 1.98 ( V O ) 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 3 μ B /cell, for Cr and Mn, and a metastable low-spin (LS) state, with 0 (Cr) and 1 (Mn) μ B /cell. For vanadium, only a state with 1 μ B /cell was found. The spin-crossover energy ( E SCO ) from the LS to the HS is 114 meV for Cr and 42 meV for Mn. By creating O vacancies close to the TM site, we show that the metastability and E SCO change. For chromium, a new HS state appears (4 μ B /cell), with an energy barrier of 32 meV relative to the 2 μ B /cell state. For manganese, the metastable LS state of 1 μ B /cell disappears, while for vanadium the HS state of 1 μ B /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.