Electron conduction mechanisms in magnetic tunnel junctions fabricated using amorphous Si-Zn-Sn-O as a low-resistive semiconducting barrier

CoFeB/ Si-Zn-Sn-O /CoFeB magnetic tunnel junctions (MTJs) have been fabricated using amorphous Si-Zn-Sn-O as a low-resistive semiconducting barrier. In the low bias voltage range (up to -0.2 V), direct tunneling is found to be the dominant transport mechanism in MTJs. Tunneling conduction is further verified by simulation of tunnel current density and differential conductance using Simmon's and Brinkmann model, respectively. Simulated results provided valuable insights into the barrier properties, including interfacial barrier height, thickness, and barrier asymmetry. Above the direct tunneling regime, electron transport in MTJs is governed by Pool Frenkel emission, which possibly arises due to the presence of high-density localized tail states below the conduction band of amorphous Si-Zn-Sn-O. Tunnelling magnetoresistance value of MTJs is found to be very low, which is attributed to the presence of various inelastic conduction channels. The results of this study might be useful to explore the potential of amorphous Si-Zn-Sn-O for fabricating low-resistive MTJ based spintronic devices.

Automated summary

CoFeB/Si-Zn-Sn-O/CoFeB magnetic tunnel junctions (MTJs) with amorphous Si-Zn-Sn-O as a low-resistive semiconducting barrier were fabricated. Direct tunneling was found to be the main transport mechanism in MTJs within the low bias voltage range. Simulation results using the Simmon's and Brinkmann models provided insights into the barrier properties. In addition, Pool Frenkel emission was observed in the electron transport above the direct tunneling regime, possibly due to localized tail states in the amorphous Si-Zn-Sn-O. The low tunnelling magnetoresistance value in MTJs was attributed to the presence of various inelastic conduction channels. These findings contribute to the exploration of amorphous Si-Zn-Sn-O for low-resistive MTJ-based spintronic devices.