Electric-field-induced extremely large change in resistance in graphene ferromagnets

Yu Song
  • Journal of Physics D Applied Physics, December 2017, Institute of Physics Publishing
  • DOI: 10.1088/1361-6463/aa9b5e

Magnetic-field-free extremely large on-off ratios at high temperature

What is it about?

Modern hard-drive read heads and magnetoresistance random access memories are based on a tunneling magnetoresistance (TMR) effect in a multilayered magnetic tunneling junction structure. With much higher on-off ratio, colossal magnetoresistance (CMR) effect found in multicomponent manganite perovskites (∼100 × 1E3%) and extremely large magnetoresistance (XMR) explored in Dirac materials (~1E6%) are promising better choice. However, to achieve these CMR or XMRs, extreme high-magnetic fields and low- temperatures are required; as a result, it is not applicable for any realistic devices yet. In this work, we propose a device that can generate even higher on-off ratios at a high temperature and in a zero magnetic field. We demonstrate that, by applying a proper voltage on one of the ferromagnets, an extremely large change in resistance up to 305×1E6% can be achieved at the liquid helium temperature (4.2 K) and in a magnetic filed of 0 T. The value maintains as 16×1E3% at the liquid nitrogen temperature (77 K).

Why is it important?

Our work should be helpful for developing a realistic switching device. Using an electric field instead of a magnetic field, the proposed device is also far more energy saving and compatible with the ubiquitous voltage-controlled semiconductor technology.

Perspectives

Yu Song (Author)

The mechanism for the gate-induced and magnetic-field-free extremely large on-off ratios is an electric-field-induced reversal of the full polarization in the free ferromagnet, which results in a transition between metal and insulator states of the device. I think this mechanism can exist widely in 2D ferromagnets.

The following have contributed to this page: Yu Song