Spin transfer torque generated magnetic droplet solitons (invited)
Artikel i vetenskaplig tidskrift, 2014

We present recent experimental and numerical advancements in the understanding of spin transfer torque generated magnetic droplet solitons. The experimental work focuses on nano-contact spin torque oscillators (NC-STOs) based on orthogonal (pseudo) spin valves where the Co fixed layer has an easy-plane anisotropy, and the [Co/Ni] free layer has a strong perpendicular magnetic anisotropy. The NC-STO resistance and microwave signal generation are measured simultaneously as a function of drive current and applied perpendicular magnetic field. Both exhibit dramatic transitions at a certain current dependent critical field value, where the microwave frequency drops 10 GHz, modulation sidebands appear, and the resistance exhibits a jump, while the magnetoresistance changes sign. We interpret these observations as the nucleation of a magnetic droplet soliton with a large fraction of its magnetization processing with an angle greater than 90 degrees, i.e., around a direction opposite that of the applied field. This interpretation is corroborated by numerical simulations. When the field is further increased, we find that the droplet eventually collapses under the pressure from the Zeeman energy. (C) 2014 AIP Publishing LLC.

MULTILAYER

EXCITATION

NANO-OSCILLATORS

Physics

ELECTRIC-CURRENT

Applied

MODULATION

POLARIZED CURRENT

DRIVEN

PHYSICS

APPLIED

DEVICES

PHASE-LOCKING

EMISSION

Författare

Sunjae Chung

Göteborgs universitet

S. M. Mohseni

S. R. Sani

Ezio Iacocca

Göteborgs universitet

Randy K. Dumas

Göteborgs universitet

T. N. A. Nguyen

Yevgen Pogoryelov

Göteborgs universitet

Pranaba Muduli Kishor

Göteborgs universitet

A. Eklund

M. Hoefer

Johan Åkerman

Göteborgs universitet

Journal of Applied Physics

0021-8979 (ISSN) 1089-7550 (eISSN)

Vol. 115 artikel nr 172612-

Ämneskategorier

Fysik

DOI

10.1063/1.4870696