Spinwave

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An illustration of the precession of a spin wave about an applied magnetic field with a wavevector that is eleven times the lattice constant.

Short-wavelength spin waves generated directly for the first time

Date: July 19, 2016
Source: ScienceDaily.com from Helmholtz-Zentrum Dresden-Rossendorf
https://www.sciencedaily.com/releases/2016/07/160719105747.htm
Summary:
With the rapid advance of miniaturization, data processing using electric currents faces tough challenges, some of which are insurmountable. Magnetic spin waves are a promising alternative for the transfer of information in even more compact chips. Scientists have now succeeded in generating spin waves with extremely short wavelengths in the nanometer range -- a key feature for their future application.
Retrieved by Admin (talk) 16:02, 25 July 2016 (EDT) from https://www.sciencedaily.com/releases/2016/07/160719105747.htm

Inverse spin-Hall effect in palladium at room temperature

K. Ando and E. Saitoh
(Received at Journal of Applied Physics 21 July 2010; accepted 19 October 2010; published online 15 December 2010)
“In a solid, the spin-orbit interaction enables the reciprocal conversion between spin and charge currents; the direct spin-Hall effect (DSHE) converts a charge current into a spin current and the inverse process of the DSHE, the inverse spin-Hall effect (ISHE), converts a spin current into electric voltage. The effectiveness of this spin-charge conversion is characterized by the spin-Hall angle θSHE = σSHEc, where σSHE and σc are spin-Hall conductivity and electrical conductivity, respectively. Since the DSHE and ISHE enable the electric generation and detection of spin currents, the spin-Hall angle is an essential parameter for the integration of spin current technologies into electronic technologies based on a charge current.
More –Journal of Applied Physics http://jap.aip.org/resource/1/japiau/v108/i11/p113925_s1?view=fulltext&bypassSSO=1#s2



Researchers Control Collective Spin States Electrically at Room Temperature

Source: National Science Foundation http://www.nsf.gov/discoveries/disc_summ.jsp?org=NSF&cntn_id=117382&preview=false


Now, new lab work at the University of Nebraska Lincoln (UNL) Materials Science and Engineering Center (MRSEC) may have made a significant breakthrough in the field of spintronics. Physicists there, led by professor Christian Binek, for the first time changed the orientation of a very large number of electron spins collectively at room temperature by pure electrical means, a feat that eventually could make devices that use spintronics more readily available for everyday uses.

Letter: Nature 464, 262-266 (11 March 2010)

Transmission of electrical signals by spin-wave interconversion in a magnetic insulator

Correspondence to: E. Saitoh1,2,4

Received 28 September 2009; Accepted 1 February 2010

Y. Kajiwara1,2, K. Harii1, S. Takahashi1,3, J. Ohe1,3, K. Uchida1, M. Mizuguchi1, H. Umezawa5, H. Kawai5, K. Ando1,2, K. Takanashi1, S. Maekawa1,3 & E. Saitoh1,2,4
1. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
2. Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
3. CREST,
4. PRESTO, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan
5. FDK Corporation, Shizuoka 431-0495, Japan

“The energy bandgap of an insulator is large enough to prevent electron excitation and electrical conduction1. But in addition to charge, an electron also has spin2, and the collective motion of spin can propagate–and so transfer a signal–in some insulators3. This motion is called a spin wave and is usually excited using magnetic fields.

Here we show that a spin wave in an insulator can be generated and detected using spin–Hall effects, which enable the direct conversion of an electric signal into a spin wave, and its subsequent transmission through (and recovery from) an insulator over macroscopic distances.

First, we show evidence for the transfer of spin angular momentum between an insulator magnet Y3Fe5O12 and a platinum film. This transfer allows direct conversion of an electric current in the platinum film to a spin wave in the Y3Fe5O12 via spin–Hall effects4, 5, 6, 7, 8, 9, 10, 11.

Second, making use of the transfer in a Pt/Y3Fe5O12/Pt system, we demonstrate that an electric current in one metal film induces voltage in the other, far distant, metal film. Specifically, the applied electric current is converted into spin angular momentum owing to the spin-Hall effect7, 8, 10, 11 in the first platinum film; the angular momentum is then carried by a spin wave in the insulating Y3Fe5O12 layer; at the distant platinum film, the spin angular momentum of the spin wave is converted back to an electric voltage.

This effect can be switched on and off using a magnetic field.

Weak spin damping3 in Y3Fe5O12 is responsible for its transparency for the transmission of spin angular momentum. This hybrid electrical transmission method potentially offers a means of innovative signal delivery in electrical circuits and devices.


Source: nature.com doi–10.1038/nature08876 (http://www.nature.com/nature/journal/v464/n7286/full/nature08876.html)

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Journal of Applied Physics

Intrinsic ambient ferromagnetism in ZnO:Co induced by Eu codoping

M. H. N. Assadi, Y. B. Zhang, P. Photongkam, and S. Li
School of Materials Science and Engineering, The University of New South Wales, Sydney, Australia
(Received 9 August 2010; accepted 23 November 2010; published online 10 January 2011)
We manipulate the interaction of Co’s 3d and Eu’s 4f electrons to design and fabricate ZnO:Co+Eu, which possesses intrinsic ferromagnetism at ambient temperature. The results show that the Eu ions tend to neighboring Co ions in order to eliminate the lattice distortion caused by the larger Eu ions via strain coupling. It was also revealed that the preference of parallel spin alignment between Eu and Co ions results in ferromagnetism. The theoretical analyses and our experimental results evidenced that the induced ferromagnetism in the Eu and Co codoped ZnO is intrinsic at ambient temperature.
© 2011 American Institute of Physics



See also

Google search —spinwave
Spin Wave Wikipedia.org
Electrical signals transmitted via spin waves Mar 12, 2010 (PhysicsWorld.com)
Understanding coherent microscopic spin process I-CAMP 2010 Australia CIMOPV Friday July 2 Dane McCamey
Magnetic Vortex-Spinwave Scattering Functions, G. M. Wysin, Kansas State University, Spring 2000