The current-induced magnetization switching (spin transfer effect) in a low resistance-area (RA) product magnetic tunnel junction (MTJ) device with critical current density of 1.4 × 107 A/cm2 was demonstrated. The RA product of the MTJ is 4.2 Ωμm2 and the magnetoresistance (MR) ratio induced by current is up to 16%. An MTJ structure with a novel nano-current-channel (NCC) layer inserted into the free layer for the current-induced magnetization switching by lower current density was proposed and prototyped. By using the current confined effect, the local current density in the integrated free layer was sufficiently high to switch the magnetization locally. Such local magnetization reversal helped to reverse the magnetic moments around together with the polarized current and spread out the switching of the entire free layer through the superparamagnetic nano-channels. The critical current density was reduced to 4.2 × 106 A/cm 2, which is only one quarter of that for a pure MTJ structure.
Bibliographical noteFunding Information:
This work was supported in part by the Grant-in-Aid Fund from the University of Minnesota Graduate School and Heraeus, Inc.
Copyright 2008 Elsevier B.V., All rights reserved.
- Current-induced magnetization switching (CIMS)
- Hot spots
- Magnetic random access memory (MRAM)
- Magnetic tunnel junction (MTJ)
- Nano-current-channel (NCC)
- Nanogranular layer
- Spin torque
- Spin transfer