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Ultra-fast annealing manipulated spinodal nano-decomposition in Mn-implanted Ge
摘要： In the present work, millisecond-range flash lamp annealing is used to recrystallize Mn-implanted Ge. Through systematic investigations of structural and magnetic properties, we find that the flash lamp annealing produces a phase mixture consisting of spinodally decomposed Mn-rich ferromagnetic clusters within a paramagnetic-like matrix with randomly distributed Mn atoms. Increasing the annealing energy density from 46, via 50, to 56 J cm?2 causes the segregation of Mn atoms into clusters, as proven by transmission electron microscopy analysis and quantitatively confirmed by magnetization measurements. According to x-ray absorption spectroscopy, the dilute Mn ions within Ge are in d5 electronic configuration. This Mn-doped Ge shows paramagnetism, as evidenced by the unsaturated magnetic-field-dependent x-ray magnetic circular dichroism signal. Our study reveals how spinodal decomposition occurs and influences the formation of ferromagnetic Mn-rich Ge–Mn nanoclusters.
关键词： flash lamp annealing,ion implantation,spinodal decomposition,Ge–Mn nanoclusters
更新于2025-09-11 14:15:04
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Magnetism of Eu-doped GaN modulations by spinodal nanodecomposition
摘要： By the Monte Carlo method, magnetic properties have been investigated for Eu-doped GaN involving internal nanostructures induced by nanoscale spinodal decomposition, where these nanostructures are spontaneously or artificially formed. In the present simulations, hysteretic and nonhysteretic magnetization curves are observed in the systems with the large-sized and small-sized nanostructures, respectively. These nanostructures affect the blocking temperatures as well. Furthermore, they influence temperature-dependent energy barriers of spin flipping; therefore, the simulations suggest that the magnetization is thermally stable. However, we observe that the blocking temperatures are smaller than the experimental values, which may be due to atomic vacancies.
关键词： magnetic properties,blocking temperatures,Eu-doped GaN,Monte Carlo method,spinodal decomposition
更新于2025-09-04 15:30:14