Large time-dependent coercivity and resistivity modification under sustained voltage application in a Pt/Co/AlOx/Pt junction

Abstract

The coercivity and resistivity of a Pt/Co/AlOx/Pt junction are measured under sustained voltage application. High bias voltages of either polarity are determined to cause a strongly enhanced, reversible coercivity modification compared to low voltages. Time-resolved measurements show a logarithmic development of the coercive field in this regime, which continues over a period as long as thirty minutes. Furthermore, the resistance of the dielectric barrier is found to change strongly and reversibly on the same time scale, suggesting an electrochemical process is taking place within the dielectric. It is argued that the migration of oxygen vacancies at the magnet/oxide interface could explain both the resistance variation and the enhanced electric field effect at high voltages. A thermal fluctuation aftereffect model is applied to account for the observed logarithmic dependence.

Magneto-ionic suppression of magnetic vortices

“…For oxygen magneto-ionics, the most commonly utilized solid electrolytes are Gd 2 O 3 , [34,49,[57][58][59] HfO 2 , [61,62] or Al 2 O 3 [64]. All these materials are characterized with high ionic conductivity.…”

Voltage-controlled ON switching and manipulation of magnetization via the redox transformation of β-FeOOH nanoplatelets

“…This has enabled consider able manipulation of, e.g. magnetization [5][6][7], magnetic anisotropy [2,8,9], coercivity [10,11], domain wall pinning [3] and exchange bias [12]. In contrast to capacitive electronic charging and most other magnetoelectric approaches that are volatile and require the constant application of voltage, magnetoionic effects can persist after the voltage has been switched off [12][13][14].…”

“…To date, such redoxbased voltage control of magnetism is mainly studied for ultrathin films with thickness of or below few nanometers [9,10,13,14,17,18]. Since the magneto ionic mechanism is based on interface reactions, an increase of the surface/volume ratio and the use of porous structures are promising routes to the magnetoionic control of larger structures [5,6].…”