756 research outputs found
Topological chiral magnonic edge mode in a magnonic crystal
Topological phases have been explored in various fields in physics such as
spintronics, photonics, liquid helium, correlated electron system and
cold-atomic system. This leads to the recent foundation of emerging materials
such as topological band insulators, topological photonic crystals and
topological superconductors/superfluid. In this paper, we propose a topological
magnonic crystal which provides protected chiral edge modes for magnetostatic
spin waves. Based on a linearized Landau-Lifshitz equation, we show that a
magnonic crystal with the dipolar interaction acquires spin-wave volume-mode
band with non-zero Chern integer. We argue that such magnonic systems are
accompanied by the same integer numbers of chiral spin-wave edge modes within a
band gap for the volume-mode bands. In these edge modes, the spin wave
propagates in a unidirectional manner without being scattered backward, which
implements novel fault-tolerant spintronic devices.Comment: 12 pages, 7 figure
Mesoscopic Hall effect driven by chiral spin order
A Hall effect due to spin chirality in mesoscopic systems is predicted. We
consider a 4-terminal Hall system including local spins with geometry of a
vortex domain wall, where strong spin chirality appears near the center of
vortex. The Fermi energy of the conduction electrons is assumed to be
comparable to the exchange coupling energy where the adiabatic approximation
ceases to be valid. Our results show a Hall effect where a voltage drop and a
spin current arise in the transverse direction. The similarity between this
Hall effect and the conventional spin Hall effect in systems with spin-orbit
interaction is pointed out.Comment: 4 pages, 4 figure
Conductance fluctuations in the presence of spin scattering
Electron transport through disordered systems that include spin scatterers is
studied numerically. We consider three kinds of magnetic impurities: the Ising,
the XY and the Heisenberg. By extending the transfer matrix method to include
the spin degree of freedom, the two terminal conductance is calculated. The
variance of conductance is halved as the number of spin components of the
magnetic impurities increases. Application of the Zeeman field in the lead
causes a further halving of the variance under certain conditions.Comment: to be published in Phys. Rev.
Osimertinib in Untreated EGFR-Mutated Advanced Non-Small-Cell Lung Cancer
FLAURA ClinicalTrials.gov number, NCT02296125BACKGROUND:
Osimertinib is an oral, third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations. We compared osimertinib with standard EGFR-TKIs in patients with previously untreated, EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC).
METHODS:
In this double-blind, phase 3 trial, we randomly assigned 556 patients with previously untreated, EGFR mutation-positive (exon 19 deletion or L858R) advanced NSCLC in a 1:1 ratio to receive either osimertinib (at a dose of 80 mg once daily) or a standard EGFR-TKI (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily). The primary end point was investigator-assessed progression-free survival.
RESULTS:
The median progression-free survival was significantly longer with osimertinib than with standard EGFR-TKIs (18.9 months vs. 10.2 months; hazard ratio for disease progression or death, 0.46; 95% confidence interval [CI], 0.37 to 0.57; P<0.001). The objective response rate was similar in the two groups: 80% with osimertinib and 76% with standard EGFR-TKIs (odds ratio, 1.27; 95% CI, 0.85 to 1.90; P=0.24). The median duration of response was 17.2 months (95% CI, 13.8 to 22.0) with osimertinib versus 8.5 months (95% CI, 7.3 to 9.8) with standard EGFR-TKIs. Data on overall survival were immature at the interim analysis (25% maturity). The survival rate at 18 months was 83% (95% CI, 78 to 87) with osimertinib and 71% (95% CI, 65 to 76) with standard EGFR-TKIs (hazard ratio for death, 0.63; 95% CI, 0.45 to 0.88; P=0.007 [nonsignificant in the interim analysis]). Adverse events of grade 3 or higher were less frequent with osimertinib than with standard EGFR-TKIs (34% vs. 45%).
CONCLUSIONS:
Osimertinib showed efficacy superior to that of standard EGFR-TKIs in the first-line treatment of EGFR mutation-positive advanced NSCLC, with a similar safety profile and lower rates of serious adverse events. (Funded by AstraZeneca; FLAURA ClinicalTrials.gov number, NCT02296125 .).info:eu-repo/semantics/publishedVersio
Charge and Spin Currents Generated by Dynamical Spins
We demonstrate theoretically that a charge current and a spin current are
generated by spin dynamics in the presence of spin-orbit interaction in the
perturbative regime. We consider a general spin-orbit interaction including the
spatially inhomogeneous case. Spin current due to spin damping is identified as
one origin of generated charge current, but other contributions exist, such as
the one due to an induced conservative field and the one arising from the
inhomogeneity of spin-orbit interaction.Comment: 14 pages, 4 figure
Effective magnetization damping for a dynamical spin texture in metallic ferromagnet
An additional magnetization damping for an inhomogeneous spin texture in metallic ferromagnets is calculated
on the basis of the s–d exchange model. The effect of conduction electrons on the magnetization dynamics is
accounted for the case of slowly varying spin texture within adiabatic approximation by using a coordinate transformation
to the local quantization axis. The moving magnetic vortex in a circular nanodot made of permalloy is
considered as an example. The dependence of the damping on the dot geometrical sizes is obtained. It is found
that the additional damping can reach up to 50% of magnitude of the phenomenological Gilbert damping in the
Landau–Lifshitz equation of magnetization motion and should be taken into account for any inhomogeneous
spin texture dynamics in ferromagnetic metals
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