• Santos, Elton J. G.
• Liu, Yu
• Singamaneni, Srinivasa R.
• Sreenivasan, Sreeprasad T.
• Petrovic, Cedomir
• Biacchi, Adam
• Sanad, Mohamed Fathi
• Augustin, Mathias
• Martinez, Luis M.
• Iturriaga, Hector

Abstract

<jats:title>Abstract</jats:title><jats:p>Among several well-known transition metal-based compounds, cleavable van der Waals (vdW) Fe<jats:sub>3-x</jats:sub>GeTe<jats:sub>2</jats:sub> (FGT) magnet is a strong candidate for use in two-dimensional (2D) magnetic devices due to its strong perpendicular magnetic anisotropy, sizeable Curie temperature (T<jats:sub>C</jats:sub> ~154 K), and versatile magnetic character that is retained in the low-dimensional limit. While the T<jats:sub>C</jats:sub> remains far too low for practical applications, there has been a successful push toward improving it via external driving forces such as pressure, irradiation, and doping. Here we present experimental evidence of a room temperature (RT) ferromagnetic phase induced by the electrochemical intercalation of common tetrabutylammonium cations (TBA+) into quasi-2D FGT. We obtained Curie temperatures as high as 350 K with chemical and physical stability of the intercalated compound. The temperature-dependent Raman measurements, in combination with vdW-corrected ab initio calculations, suggest that charge transfer (electron doping) upon intercalation could lead to the observation of RT ferromagnetism. This work demonstrates that molecular intercalation is a viable route in realizing high-temperature vdW magnets in an inexpensive and reliable manner, and has the potential to be extended to bilayer and few-layer vdW magnets.</jats:p>

Topics

• impedance spectroscopy
• compound
• phase
• two-dimensional
• Curie temperature