Unipolar resistive switching in CoFeB∕MgO∕CoFeB magnetic tunnel junction

Abstract

We found that a magnetic tunnel junction (MTJ) shows two types of memory operation. One is spin torque switching, and the other is electric stress induced resistive switching (RS), which is observed in various metal oxides. A MTJ in RS operation exhibits a resistance ratio of greater than 100, an endurance of more than 400cycles, and data retention in excess of 89h at 85°C, which is suitable for programable switch elements. The MTJ can operate as a programable switch, as well as a storage element, in a field programable gate array.

Random barrier double-well model for resistive switching in tunnel barriers

“…[9][10][11][12][13][14] We showed, for instance, that MgO tunnel barriers with a few atomic layers of chromium 14 or vanadium 15 at the MgO interface exhibited reproducible switching effects in Fe/Cr/MgO/Fe or Fe/V/MgO/Fe systems. This was attributed to the creation of oxygen vacancies in MgO at the interface with these "dusting" layers.…”

The Memristive Magnetic Tunnel Junction as a Nanoscopic Synapse‐Neuron System

“…[20,21] This spin-transfer torque (STT) switching makes the external magnetic field obsolete and allows for MTJs to be classified as current-driven memristive devices. [22] Here, we report on memristive MTJs [23][24][25][26] characterized by the simultaneous occurrence of RS and TMR. [4,5] We demonstrate that these systems intrinsically exhibit characteristics of synapses and neurons.…”

Tuning of magnetization dynamics in sputtered CoFeB thin film by gas pressure

“…Tuning of magnetization dynamics in sputtered CoFeB thin film by gas pressure Feng Xu, 1,2,a) Qijun Huang, 1 Zhiqin Liao, 1 Shandong Li, 3 The influences of sputtering gas pressure on the high-frequency magnetization dynamics of as-sputtered CoFeB thin films are studied with permeability spectra based on the Landau-LifshitzGilbert (LLG) equation. Results show that with the pressure increasing, both the anisotropy field and resonance frequency have minimums, while the initial permeability shows a maximum.…”

“…3 Benefiting from its amorphous nature, the MTJ's with CoFeB can have an especially high tunnel magnetoresistance (TMR) effect. 3 The dynamic soft magnetic properties of CoFeB, however, have not been carefully studied, until recently by Bilzer et al 4 A low Gilbert damping was obtained in CoFeB thin films, and the damping can be increased by annealing the thin films to crystallization. 4 The tuning of damping is always an important issue in the high-frequency dynamics of soft magnetic thin films.…”