Efficient Spin‐Orbit Torque Switching of the Semiconducting Van Der Waals Ferromagnet Cr<sub>2</sub>Ge<sub>2</sub>Te<sub>6</sub>

Vaibhav Ostwal, Tingting Shen, Joerg Appenzeller

Advanced Materials · 2020 · 134 citations · 18 references

Concepts

TL;DR

Electrical manipulation of magnetic properties in van der Waals ferromagnets is essential for their integration into future spintronics devices. The study aims to manipulate the magnetization of thin Cr₂Ge₂Te₆ flakes using an in‑plane magnetic field and a charge current through Ta. The authors investigate Cr₂Ge₂Te₆/Ta heterostructures by measuring anomalous Hall effect while applying an in‑plane magnetic field and a charge current through Ta to generate spin Hall torque. Thinner Cr₂Ge₂Te₆ flakes show stronger out‑of‑plane hysteresis, and with 20 mT in‑plane fields a charge current density as low as 5 × 10⁵ A cm⁻² switches the magnetization—two orders of magnitude lower than for CoFeB—highlighting the low‑power potential of 2D ferromagnets for memory and logic.

Abstract

Abstract Being able to electrically manipulate the magnetic properties in recently discovered van der Waals ferromagnets is essential for their integration in future spintronics devices. Here, the magnetization of a semiconducting 2D ferromagnet, i.e., Cr 2 Ge 2 Te 6 , is studied using the anomalous Hall effect in Cr 2 Ge 2 Te 6 /tantalum heterostructures. The thinner the flakes, hysteresis and remanence in the magnetization loop with out‐of‐plane magnetic fields become more prominent. In order to manipulate the magnetization in such thin flakes, a combination of an in‐plane magnetic field and a charge current flowing through Ta—a heavy metal exhibiting giant spin Hall effect—is used. In the presence of in‐plane fields of 20 mT, charge current densities as low as 5 × 10 5 A cm –2 are sufficient to switch the out‐of‐plane magnetization of Cr 2 Ge 2 Te 6 . This finding highlights that current densities required for spin‐orbit torque switching of Cr 2 Ge 2 Te 6 are about two orders of magnitude lower than those required for switching nonlayered metallic ferromagnets such as CoFeB. The results presented here show the potential of 2D ferromagnets for low‐power memory and logic applications.

References

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