10 research outputs found
First-principles study of the spin-mixing conductance in Pt/NiFe junctions
Based on the spin-pumping theory and first-principles calculations, the
spin-mixing conductance (SMC) is theoretically studied for Pt/Permalloy
(NiFe, Py) junctions. We evaluate the SMC for ideally clean Pt/Py
junctions and examine the effects of interface randomness. We find that the SMC
is generally enhanced in the presence of interface roughness as compared to the
ideally clean junctions. Our estimated SMC is in good quantitative agreement
with the recent experiment for Pt/Py junctions. We propose possible routes to
increase the SMC in Pt/Py junctions by depositing a foreign magnetic metal
layer in Pt, offering guidelines for designing the future spintronic devices.Comment: Accepted for publication in Applied Physics Letter
Towards precise measurement of oscillatory domain wall by ferromagnetic Josephson junction
We theoretically propose a principle for precise measurement of oscillatory
domain wall (DW) by a ferromagnetic Josephson junction, which is composed of a
ferromagnetic wire with DW and two superconducting electrodes. The
current-voltage curve exhibits stepwise structures, only when DW oscillates in
the ferromagnetic wire. The voltage step appears at V = n(\hbar/2e)\omega_DW
with the fundamental constant \hbar/e, integer number n, and the DW frequency
\omega_DW. Since V can be determined in the order of 10^9 accuracy, the
oscillatory DW will be measured more precisely than present status by
conventional method.Comment: 3 pages, 2 figure
Optical properties of N+ ion-implanted and rapid thermally annealed Si(100) wafers studied by spectroscopic ellipsometry
The optical properties of N+ ion-implanted Si(100) wafers have been studied using the spectroscopic
ellipsometry (SE). The N+ ions are implanted at 150 keV with fluences in the range between 1
×10↑16 and 7.5×10↑16 cm−2 at room temperature. A Bruggeman effective-medium-approximation
and a linear-regression analysis require a four-phase model (substrate/first and second damaged
layers/ambient) to explain the experimental data of the as-implanted samples. These analyses
suggest that the buried fully amorphous layer can be formed at around ~5×10↑16 cm−2 dose. The
rapid thermal annealing is performed at 750°C in a dry N2 atmosphere on N+ ion-implanted
samples. The SE data reveal that the recrystallization starts to occur very quickly. The time constant
for the defect annealing in the deeper damaged layer is determined to be 36 s. The
dielectric-function spectra ε(E) of microcrystalline silicon deduced here differ appreciably from that
of the single-crystalline silicon, especially in the vicinity of the critical points