41 research outputs found
Scaling of Berry-curvature monopole dominated large linear positive magnetoresistance
The linear positive magnetoresistance (LPMR) is a widely observed phenomenon
in topological materials, which is promising for potential applications on
topological spintronics. However, its mechanism remains ambiguous yet and the
effect is thus uncontrollable. Here, we report a quantitative scaling model
that correlates the LPMR with the Berry curvature, based on a ferromagnetic
Weyl semimetal CoS2 that bears the largest LPMR of over 500% at 2 Kelvin and 9
Tesla, among known magnetic topological semimetals. In this system, masses of
Weyl nodes existing near the Fermi level, revealed by theoretical calculations,
serve as Berry-curvature monopoles and low-effective-mass carriers. Based on
the Weyl picture, we propose a relation , with B being the applied magnetic field and the average Berry curvature near the Fermi surface, and further
introduce temperature factor to both MR/B slope (MR per unit field) and
anomalous Hall conductivity, which establishes the connection between the model
and experimental measurements. A clear picture of the linearly slowing down of
carriers, i.e., the LPMR effect, is demonstrated under the cooperation of the
k-space Berry curvature and real-space magnetic field. Our study not only
provides an experimental evidence of Berry curvature induced LPMR for the first
time, but also promotes the common understanding and functional designing of
the large Berry-curvature MR in topological Dirac/Weyl systems for magnetic
sensing or information storage
Large anomalous Hall effect in a hexagonal ferromagnetic Fe5Sn3 single crystal
In this paper, we report an experimental observation of the large anomalous
Hall effect (AHE) in a hexagonal ferromagnetic Fe5Sn3 single crystal with
current along the b axis and a magnetic field normal to the bc plane. The
intrinsic contribution of the anomalous Hall conductance sigma_AH^int was
approximately 613 {\Omega}-1 cm-1, which was more than 3 times the maximum
value in the frustrated kagome magnet Fe3Sn2 and nearly independent of the
temperature over a wide range between 5 and 350 K. The analysis results
revealed that the large AHE was dominated by a common, intrinsic term, while
the extrinsic contribution, i.e., the skew scattering and side jump, turned out
to be small. In addition to the large AHE, it was found the types of majority
carriers changed at approximately 275 and 30 K, consistent with the critical
temperatures of the spin reorientation. These findings suggest that the
hexagonal ferromagnetic Fe5Sn3 single crystal is an excellent candidate to use
for the study of the topological features in ferromagnets.Comment: accepted as a rapid communication in Phy. Rev.
Recommended from our members
35 W continuous-wave Ho:YAG single-crystal fiber laser
We report on a high-power Ho:YAG single-crystal fiber (SCF) laser inband pumped by a high-brightness Tm-fiber laser at 1908 nm. The Ho:YAG SCF grown by the micro-pulling-down technique exhibits a propagation loss of at. A continuous-wave output power of 35.2 W is achieved with a slope efficiency of 42.7%, which is to the best of our knowledge the highest power ever reported from an SCF-based laser in the 2 spectral range. © 2020 The Author(s). Published by Cambridge University Press in association with Chinese Laser Press
Supporting Information - Atomically precise photothermal nanomachines
Histology images raw data</p