Research Highlights Archive
Magnetic field resilient superconducting fractal resonators for coupling to free spins
S. E. de Graaf, A. V. Danilov, A. Adamyan, T. Bauch, and S. E. Kubatkin
Swedish researchers demonstrate a planar superconducting microwave resonator intended for use in applications requiring strong magnetic fields and high quality factors. In perpendicular magnetic fields of 20 mT the resonators maintain a quality factor above 25000 over a wide range of applied powers, down to single photon population. In parallel field the same quality factor is observed above 160 mT, the field required for coupling to free spins at a typical operating frequency of 5 GHz.
Selective nucleation induced by defect nanostructures: A way to control cobalt disilicide precipitation during ion implantation
F. Fortuna, M.-A. Nguyen, M.-O. Ruault, M. A. Kirk, V. A. Borodin, and M. G. Ganchenkova
The nucleation of new phases in silicon by means of ion implantation is a complicated phenomenon. Ion implantation is usually accompanied by creation of radiation damage in the form of self-interstitial atoms, vacancies, and small defect clusters. The interaction between implanted atoms and radiation damage is typically synergetic and often is strongly affected by other components of defect microstructure and sample free surfaces. A proper understanding of the mechanisms of this interaction opens a way to control the implanted ion precipitation through the deliberate adjustment of local environment for precipitate nucleation. In this paper, we demonstrate an example of such a control, using a model system where cobalt disilicide precipitates nucleate and grow during high-temperature implantation of Si specimens with Co ions.
Thin-film silicon triple-junction solar cell with 12.5% stable efficiency on innovative flat light-scattering substrate
Karin Söderström, Grégory Bugnon, Rémi Biron, Céline Pahud, Fanny Meillaud, Franz-Josef Haug, and Christophe Ballif
Several thin-film solar cell technologies require light-trapping schemes that are predominantly based on depositing the solar cells on rough surfaces. While this approach efficiently increases the density of photo-generated carriers, open-circuit voltage and fill factor generally decrease. Recently, researchers from the Swiss Photovoltaics and Thin-Film Electronics Laboratory explored the benefits of a newly developed substrate that decouples the growth and scattering interfaces in n-i-p triple-junction solar cells for the first time.
Electrical potential measurement in plasma columns of atmospheric plasma jets
Gunagsup Cho, Junghyun Kim, Hanlim Kang, Yunjung Kim, Gi-Chung Kwon, and Han S. Uhm
In medicine, plasma “pencils” are often used on human tissue for surgery or sterilization. Researchers from Kwangwoon University in South Korea examine the electrical potential of atmospheric plasma jets to understand the risks for patients of electric shock.
Swing switching of spin-torque valves
Tom Dunn and Alex Kamenev
Using an effect similar to using a weak near-resonant push to drive a swing into high amplitude motion, Tom Dunn and Alex Kamenev propose a method for inducing magnetization reversal in magnetic tunnel junctions via an optimal “AC perpendicular method”.
Effect of capacitive coupling in a miniature inductively coupled plasma source
Yoshinori Takao, Koji Eriguchi, and Kouichi Ono
Researchers in Japan have conducted two-dimensional axisymmetric particle-in-cell simulations with a Monte Carlo collision algorithm to investigate the effect of capacitive coupling in a miniature inductively coupled plasma source by using two models: an inductive model and a hybrid model. They present conclusions and recommendations for these systems.
Magnetically and thermally induced switching processes in hard magnets
Christian Behler, Volker Neu, Ludwig Schultz, and Sebastian Fähler
Magnetic switching can occur under the influence of external magnetic fields and/or thermal activation. To separate the role of both effects, researchers from Dresden have analyzed, as an example, an epitaxial FePt film with a mesoscopic grain size by angular and time dependent magnetization measurements.
Charging effect simulation model used in simulations of plasma etching of silicon
Valentyn Ishchuk, Burkhard E. Volland, Maik Hauguth, Mike Cooke, and Ivo W. Rangelow
Understanding the consequences of local surface charging on the evolving etching profile is a critical challenge in high density plasma etching. Deflection of the positively charged ions in locally varying electric fields can cause profile defects such as notching, bowing, and microtrenching. Researchers from Ilmenau University of Technology have developed a numerical simulation model capturing the influence of the charging effect over the entire course of the etching process.
Electrically tunable electron spin lifetimes in GaAs(111)B quantum wells
K. Biermann, A. Hernández-Mínguez, R. Hey, and P. V. Santos
A team of researchers in Germany investigate the electric tunability of the electron spin lifetime in GaAs(111) quantum wells inserted in biased p-i-n and n-i-p diode-like structures. Spin lifetimes from below 100 ps at an electric field of -20 kV/cm to values exceeding 4~ns at +8 kV/cm have been measured in 25 nm thick multiple quantum wells at a temperature of 20 K.
Room temperature microwave-assisted recording on 500-Gbpsi-class perpendicular medium
Y. Nozaki, N. Ishida, Y. Soeno, and K. Sekiguchi
Collaborating researchers in Japan present propose a method of evaluating the magnetization of a CoCrPt-based granular medium using vector network analyzer ferromagnetic resonance spectroscopy (FMR). These experimental techniques enable them to directly compare the relevant microwave frequency required for the most efficient microwave-assisted magnetic recording with the FMR frequency of the medium. The comparison is essential for confirming the occurrence of recording in the medium at room temperature.