Guda, A.A.; Smolentsev, N.; Rovezzi, M.; Kaidashev, E.M.; Kaydashev, V.E.; Kravtsova, A.N.; Mazalova, V.L.; Chaynikov, A.P.; Weschke, E.; Glatzel, P.; Soldatov, A.V.: Spin-polarized electronic structure of the core-shell ZnO/ZnO:Mn nanowires probed by X-ray absorption and emission spectroscopy. Journal of Analytical Atomic Spectrometry 28 (2013), p. 1629-1637
10.1039/c3ja50153a
Open Access Version (externer Anbieter)
Abstract:
The combination of X-ray spectroscopy methods complemented with theoretical analysis unravels the coexistence of paramagnetic and antiferromagnetic phases in the Zn0.9Mn0.1O shell deposited onto array of wurtzite ZnO nanowires. The shell is crystalline with orientation toward the ZnO growth axis, as demonstrated by X-ray linear dichroism. EXAFS analysis confirmed that more than 90% of Mn atoms substituted Zn in the shell while a fraction of secondary phases was below 10%. The value of manganese spin magnetic moment was estimated from the Mn K beta X-ray emission spectroscopy to be 4.3 mu(B) which is close to the theoretical value for substitutional Mn-Zn. However the analysis of L-2,L-3 X-ray magnetic circular dichroism data showed paramagnetic behaviour with saturated spin magnetic moment value of 1.95 mu(B) as determined directly from the spin sum rule. After quantitative analysis employing atomic multiplet simulations such difference was explained by a coexistence of paramagnetic phase and local antiferromagnetic coupling of Mn magnetic moments. Finally, spin-polarized electron density of states was probed by the spin-resolved Mn K-edge XANES spectroscopy and consequently analyzed by band structure calculations.