Current-induced phase transition in ballistic Ni nanocontacts

Local phase transition from ferromagnetic to paramagnetic state in the region of the ballistic Ni nanocontacts (NCs) has been experimentally observed. We found that contact size reduction leads to an increase in the bias voltage at which the local phase transition occurs. Presented theoretical interpretation of this phenomena takes into the account the specificity of the local heating of the ballistic NC and describes the electron's energy relaxation dependences on the applied voltage. The experimental data are in good qualitative and quantitative agreement with the theory proposed.Comment: 8 pages, 2 figure

Ballistic and Diffuse Electron Transport in Nanocontacts of Magnetics

The transition from the ballistic electron transport to the diffuse one is experimentally observed in the study of the magnetic phase transition in Ni nanocontacts with different sizes. It is shown that the voltage $U_C$ needed for Joule heating of the near-contact region to the critical temperature does not depend on the contact size only in the diffuse mode. For the ballistic contact it increases with decrease in the nanocontact size. The reduction of the transport electron mean free path due to heating of NCs may result in change of the electron transport mode from ballistic to diffusive one.Comment: 7 pages, 2 figures accepted for the publication in JETPL (http://www.jetpletters.ac.ru). Will be published on 25 april 201

Structural and optical properties of thin-film GeSi alloy with Ag nanoparticles obtained by ion implantation and laser irradiation

В данной работе впервые изучено влияние импульсного лазерного отжига (ИЛО) излучением рубинового лазера на слои монокристаллического Si, имплантированного ионами Ge+и Ag+, с целью создания кристаллического композитного плазмонного материала Ag:GeSi. Изучена трансформация структуры слоя и его оптического отражения в зависимости от режимов отжига.In this work for the first time the effect of pulsed laser annealing by ruby laser radiation to monocrystalline Si layers implanted by Ge+and Ag+ ions in order to produce crystalline composite plasmonic Ag:GeSi material is studied. The transformation of layer structure and its optical reflectance depending on annealing regimes is investigated.Работа выполнена при финансовой поддержке РНФ № 17-12-01176

The Effect of Pulsed Laser Radiation on a Si Layer with a High Dose of Implanted Ag⁺ Ions

© 2018, Pleiades Publishing, Ltd. Abstract: With the purpose of creating a thin composite layer of Ag:Si containing Ag nanoparticles (NPs), the effect of a nanosecond pulse produced by ruby laser (λ = 0.694 µm) on single-crystal c-Si implanted with a high dose of Ag+ ions is studied. The pulsed laser annealing (PLA) is carried out with an energy density exceeding the melting threshold of amorphous а-Si (W ≥ 1.2 J/cm2). During the PLA, temporal dynamics of reflectivity R(t) of probing laser radiation (λ = 1.064 µm) from the Ag:Si layer is explored and compared to data on the melt existence time obtained by the computer simulation. The morphology of the surface, crystallinity, and spectral optical reflection R(λ) of Ag:Si layers subject to PLA are studied. PLA is found to cause melting and subsequent crystallization of the implanted а-Si with ion-synthesized Ag NPs. In addition, a decrease of the surface roughness from 9 to 3–4 nm and redistribution of Ag NP sizes into two fractions—fine (5–15 nm) and larger (40–60 nm)—are observed. The weakening of plasmon intensity Ag NPs in Si (λmax = 835 nm) is observed in R(λ) spectra of an Ag:Si layer after PLA as compared with the initial implanted surface. This weakening may be caused by a decrease in concentration of Ag atoms in the immediate proximity to the surface as a result of Ag impurity partial diffusion within the melted layer, as well as Ag partial evaporation during the PLA

The Effect of Pulsed Laser Radiation on a Si Layer with a High Dose of Implanted Ag⁺ Ions

© 2018, Pleiades Publishing, Ltd. Abstract: With the purpose of creating a thin composite layer of Ag:Si containing Ag nanoparticles (NPs), the effect of a nanosecond pulse produced by ruby laser (λ = 0.694 µm) on single-crystal c-Si implanted with a high dose of Ag+ ions is studied. The pulsed laser annealing (PLA) is carried out with an energy density exceeding the melting threshold of amorphous а-Si (W ≥ 1.2 J/cm2). During the PLA, temporal dynamics of reflectivity R(t) of probing laser radiation (λ = 1.064 µm) from the Ag:Si layer is explored and compared to data on the melt existence time obtained by the computer simulation. The morphology of the surface, crystallinity, and spectral optical reflection R(λ) of Ag:Si layers subject to PLA are studied. PLA is found to cause melting and subsequent crystallization of the implanted а-Si with ion-synthesized Ag NPs. In addition, a decrease of the surface roughness from 9 to 3–4 nm and redistribution of Ag NP sizes into two fractions—fine (5–15 nm) and larger (40–60 nm)—are observed. The weakening of plasmon intensity Ag NPs in Si (λmax = 835 nm) is observed in R(λ) spectra of an Ag:Si layer after PLA as compared with the initial implanted surface. This weakening may be caused by a decrease in concentration of Ag atoms in the immediate proximity to the surface as a result of Ag impurity partial diffusion within the melted layer, as well as Ag partial evaporation during the PLA