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).

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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