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A new phenomenon in an old material: giant spin-phonon interaction unveiled in EuO

A new phenomenon in an old material: giant spin-phonon interaction unveiled in EuO
place:

new ANKA seminar room, building 348, 2nd floor

Affiliation:

Nanodynamics group, LAS, KIT

Date:

9.05.2016

Inviting person:

Svetoslav Stankov, KIT - IPS

Speaker:

Ramu Pradip

Time:

11:00

Europium monoxide, a rare ferromagnetic semiconductor, has been known since the early sixties mainly for its giant magneto-optic Kerr and Faraday effects, metal-to-insulator transition, colossal magnetoresistance, and anomalous Hall effect. Presently, it is one of the favored candidates for applications as a spin filter in future spintronic devices due to the large exchange splitting of its conduction band.

The lattice dynamics of EuO has very recently been determined by combining modern X-ray scattering methods with density functional theory [1]. Unexpectedly, the data analysis unveiled a remarkably strong and anisotropic spin-phonon coupling induced by the spin dynamics slightly above and well below the Curie temperature TC=69 K that remained uncovered for decades. Such strong coupling between material’s properties paves the way towards new functionalities and devices. In the light of spintronics applications, the discovery suggests that the choice of EuO single crystal orientation could be crucial for reducing the undesired spin-flips preserving the high degree of spin current polarization.

The seminar will give experimental and theoretical insights on the observed phenomenon.

 

 

[1] R. Pradip, P. Piekarz, A. Bosak, D. G. Merkel, O. Waller, A. Seiler, A. I. Chumakov, R. Rüffer, A. M. Oleś, K. Parlinski, M. Krisch, T. Baumbach, and S. Stankov

Phys. Rev. Lett.  116, 185501 (2016)