Spin-transfer torques in antiferromagnetic textures; Efficiency and quantification method

Yamane, Yuta*; Ieda, Junichi; Sinova, J.*

Physical Review B, 94(5), p.054409_1 - 054409_8, 2016/08

AA2016-0164.pdf:0.5MB

https://doi.org/10.1103/PhysRevB.94.054409

We formulate a theory of spin-transfer torques in antiferromagnets, which covers the small to large limits of the exchange coupling energy relative to the kinetic energy of the inter-sublattice electron dynamics. Our theory suggests a natural definition of the efficiency of spin-transfer torques in antiferromagnets in terms of well-defined material parameters, revealing that the charge current couples predominantly to the antiferromagnetic order parameter and the sublattice-canting moment in, respectively, the limits of large and small exchange coupling. The effects can be quantified by analyzing the antiferromagnetic spin-wave dispersions in the presence of charge current: in the limit of large exchange coupling the spin-wave Doppler shift always occurs, whereas, in the opposite limit, the only spin-wave modes to react to the charge current are ones that carry a pronounced sublattice-canting moment. The findings offer a framework for understanding and designing spin-transfer torques in antiferromagnets belonging to different classes of sublattice structures such as, e.g., bipartite and layered antiferromagnets.

Unlocking radiation resistance mechanisms; Still a long way to go

Narumi, Issei

Trends in Microbiology, 11(9), p.422 - 425, 2003/09

https://doi.org/10.1016/S0966-842X(03)00204-X

no abstracts in English

The Harmonic current control for DTQ power supplies to high intensity proton Linac

Hori, Toshihiko*; Ito, Takashi; Chishiro, Etsuji; Izumi, Keisuke*; Yamazaki, Masayoshi*; Watanabe, Kazuhiko*; Takasaki, Eiichi*; Hasegawa, Kazuo; Yoshikawa, Hiroshi

Proceedings of 27th Linear Accelerator Meeting in Japan, p.255 - 257, 2002/08

no abstracts in English

Chain oxidation initiated OH, O(P) radicals, thermal electrons, and O in electron beam irradiation of 1,2-dichloroethylenes and air mixtures

Hakoda, Teruyuki; Zhang, G.*; Hashimoto, Shoji

Radiation Physics and Chemistry, 62(2-3), p.243 - 252, 2001/09

https://doi.org/10.1016/S0969-806X(01)00194-3

no abstracts in English

All under-water experiment on the acoustic characteristic of high temperature ultrasonic transducers

Nakayama, Oukatsu;

JNC TN9400 2000-087, 74 Pages, 2000/07

JNC-TN9400-2000-087.pdf:3.25MB

We have been developing an Ultrasound Doppler Velocimetry technique (UDV), in order to apply thermo-hydraulic measurement in sodium. A feasibility study had been conducted to identify development subjects of sensor and signal processing. Thus, high temperature ultrasonic transducers were manufactured to use in water and sodium tests, which will be scheduled to optimize an algorism of signal processing and to improve the characteristic of the transducer. ln this report, we described the results of an experiment on the acoustic characteristic of transducer in water. The results are as follows : (1)The ultrasound beam profile of the transducer relating to the characteristic of velocity profile measurement using scattering ultrasound wave was obtained. The estimation of ultrasound beam profile in liquid and an ultrasound near-field region were introduced from these experimental data, (2)lt was confirmed that the frequency's spectrum of transducers are adequate for the design requirement of flow velocity range. The specifications of a transmitter and receiver for a transducer were identified, such as the amplitude gain for scattered ultrasound signal and the frequency resolution for Doppler sift signal. (3)The spatial resolution of the ultrasound beam was estimated to evaluate the accuracy of now profile measurement on UDV system.

Applications of ultrasound technique to flow velocity measurement in water experiment of inter-wrapper flow; Comparison with particle image velocimetry

Kimura, Nobuyuki; ; ; ; Kamide, Hideki; Tokuhiro, Akira; Hishida, Koichi

JNC TN9400 2000-057, 60 Pages, 2000/05

JNC-TN9400-2000-057.pdf:2.11MB

ln experimental study for the thermohydraulics of fast reactor, a simple experiment with fine measurement has been desired for understanding of phenomena and for verification of computer code rather than mockup experiments of large scale. For such purposes quality of experimental data must be improved. ln the velocity measurement, instantaneous velocity profile will have great advances for the understanding of phenomena and for the verification of computer code. ln this report two methods of the velocity profile measurement are discussed; one is ultrasound Doppler velocimetry (UDV) and the other is particle image velocimetry (PIV). These methods were applied to water experiments. The UDV was applied to pipe flow, planer jet, and the inter-wrapper flow which is seen in the gap region between subassemblies of fast reactor core. Cross check with laser Doppler velocimetly showed proper measurement of the UDV. Problems including the application to sodium experiments are also discussed. The PIV was also applied to the inter-wrapper flow. For the application to complex flow geometry, noise reduction method was developed to improve the measurement accuracy.

None

*; *

PNC TJ1575 98-001, 48 Pages, 1998/02

PNC-TJ1575-98-001.pdf:2.33MB

no abstracts in English

Development of visual beam adjustment method for the beam transport

Agematsu, Takashi; Arakawa, Kazuo; *

Proc. of 11th Symp. on Accelerator Sci. and Technol., p.446 - 448, 1997/00

no abstracts in English

A Wide band M-series signal generator using transputers

; Suzuki, Katsuo

Bunshi Kagaku Kenkyujo Gijutsu Kenkyukai Hokokushu, 0(15), p.120 - 123, 1996/07

no abstracts in English

Status report of the control system for the JAERI tandem accelerator

Hanashima, Susumu

Dai-9-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, 0, p.57 - 59, 1996/00

no abstracts in English