High power and low critical current density spin transfer torque nano-oscillators using MgO barriers with intermediate thickness

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Costa, JD (Author) Other; Serrano Guisan, S (Author) Other; Lacoste, B (Author) Other; Jenkins, AS (Author) Other; Bohnert, T (Author) Other; Tarequzzaman, M (Author) Other; Borme, J (Author) Other; Deepak, FL (Author) Other; Paz, E (Author) Other; ventura, j. (Author) FCUP; Ferreira, R (Author) Other; Freitas, PP (Author) Other

Journal

Title: Scientific Reports

Vol. 7

ISSN: 2045-2322

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 18 Citations

Scopus - 16 Citations

Other information

Authenticus ID: P-00N-GAJ

DOI: 10.1038/s41598-017-07762-z

Abstract (EN): Reported steady-state microwave emission in magnetic tunnel junction (MTJ)-based spin transfer torque nano-oscillators (STNOs) relies mostly on very thin insulating barriers [resulting in a resistance x area product (R x A) of similar to 1 Omega mu m(2)] that can sustain large current densities and thus trigger large orbit magnetic dynamics. Apart from the low R x A requirement, the role of the tunnel barrier in the dynamics has so far been largely overlooked, in comparison to the magnetic configuration of STNOs. In this report, STNOs with an in-plane magnetized homogeneous free layer configuration are used to probe the role of the tunnel barrier in the dynamics. In this type of STNOs, the RF modes are in the GHz region with integrated matched output powers (P-out) in the range of 1-40 nW. Here, P-out values up to 200 nW are reported using thicker insulating barriers for junctions with R x A values ranging from 7.5 to 12.5 Omega mu m(2), without compromising the ability to trigger self-sustained oscillations and without any noticeable degradation of the signal linewidth (Gamma). Furthermore, a decrease of two orders of magnitude in the critical current density for spin transfer torque induced dynamics (J(STT)) was observed, without any further change in the magnetic configuration.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9