Current hysteresis due to changes in magnetization of magnetic tunnel junctions by spin-polarized current

¹ Institute of Radio-Engineering & Electronics, Russian Academy of Sciences Fryazino, Vvedenskii Sq. 1, Moscow Region 141120, Russia
² University of Oxford, Department of Physics, Theoretical Physics 1 Keble Road, Oxford OX1 3NP, UK
³ Institute of Crystallography, Russian Academy of Sciences Leninskii Pr. 59, 117333 Moscow, Russia
⁴ Department of Physics, New York University 4 Washington Place, New York, NY 10003, USA
⁵ Institute of Macromolecular Compounds, Russian Academy of Sciences Bolshoy Pr. 31, 199004 St. Petersburg, Russia

Corresponding authors: carsten.heide@nyu.edu pez253@ire216.msk.su

Received: 19 October 2000
Accepted: 15 December 2000

Abstract

We measured the current-voltage characteristics of magnetic tunnel junctions using novel dielectric materials -diamond-like carbon and polyimide barriers-which have a well-controlled chemical composition. For most of our as grown samples we observed hysteresis loops which were independent of the barrier material chosen. Their non-reproducible shape was dependent on bias and external field. We ascribe the hysteresis to the existence of a dynamic change in the domain magnetization of the electrodes due to a feed-back mechanism between the tunnel current and the magnetic structure. In an external magnetic field the hysteresis loops vanish, and the current-voltage characteristics are reproducible.