High write endurance up to 1012 cycles in a spin current-type magnetic memory array

Yohei Shiokawa,Tomoyuki Sasaki,Keita Suda,Yuji Kakinuma,Eiji Komura,Atsushi Tsumita,Yugo Ishitani

doi:10.1063/1.5079917

Abstract

We demonstrated high write endurance of up to 1012 cycles with a pulse write current of 10 ns in a spin current-type (SC) single magnetic tunnel junction (MTJ) element and 8×8 memory array. Furthermore, we demonstrated an accelerated test of failure elements by increasing the write current density. According to cross-sectional TEM images of the failure MTJ elements, one of the failure models is caused only on the spin orbit torque (SOT) line by electrical-open and electrical-short conditions. We concluded that SC-MTJ will have strong write endurance against a high write current if the SOT-line is improved. SC-MTJ offers an alternative to spin transfer torque (STT)–MTJ as a high write endurance magnetic memory.

Highlights

For development and spread of the Internet of Things (IoT), an edge device with much reduced power consumption is required
The write cycle was defined as 10n cycles to apply +J to write the state of P-to-AP for 10n/2 cycles and to apply –J to write the state of AP-to-P for 10n/2 cycles
The magnetic tunnel junction (MTJ) resistance showed a little drift with increasing write cycles, a tunnel magnetoresistance (TMR) ratio of about 90 % was sustained

Summary

INTRODUCTION

For development and spread of the Internet of Things (IoT), an edge device with much reduced power consumption is required. Because of the increasing access time, higher endurance might be required to replace SRAM and to provide other types of memory optimized for AI systems in the future. To mitigate these issues, three-terminal spin orbit torque (SOT)-MRAM was proposed.. SOT effects including the spin current (spin Hall effect and/or Rashba-Edelstein effect) can switch magnetization of a free layer very rapidly (

EXPERIMENTAL PROCEDURE

RESULTS AND DISCUSSION

CONCLUSIONS