Current-driven magnetization switching in ferromagnetic bulk Rashba semiconductor (Ge,Mn)Te.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Multiferroic materials enable electrical control of magnetism via coupled ferroelectric and ferromagnetic orders.
• Polar ferromagnetic semiconductors, with broken spatial inversion and time reversal symmetries, offer new avenues for multiferroics.
• GeTe, a polar semiconductor with Rashba-type spin-split bands, serves as a base for exploring these phenomena.

Purpose of the Study:

• To investigate current-driven magnetization switching in (Ge,Mn)Te thin films.
• To explore the role of Mn doping in creating an exchange gap within the Dirac band structure.
• To understand the underlying physical mechanisms, such as the Rashba-Edelstein effect, responsible for electrical manipulation of magnetization.

Main Methods:

• Thin film deposition of (Ge,Mn)Te.
• Characterization of magnetic and electronic properties, including anomalous Hall conductivity.
• Pulse-current injection to induce and observe magnetization switching.

Main Results:

• Ferromagnetism induced by Mn doping in GeTe creates an exchange gap in the massless Dirac bands.
• Anomalous Hall conductivity increases with hole carrier density, peaking near the exchange gap.
• Electrical switching of magnetization is achieved in up to 200 nm thick (Ge,Mn)Te films via pulse-current injection.
• The observed effect is attributed to the bulk Rashba-Edelstein effect, with efficiency dependent on Fermi-level position.

Conclusions:

• Current-driven magnetization switching is successfully demonstrated in the polar ferromagnetic semiconductor (Ge,Mn)Te.
• The findings highlight the potential of magnetic bulk Rashba systems for functional correlations between electric polarization, magnetization, and current.
• This work paves the way for novel spintronic devices based on electrical control of magnetism in semiconductors.