High transport spin polarization in the van der Waals ferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Fe</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>GeTe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Deepti Rana, Monika Bhakar, G. Basavaraja, Satyabrata Bera, Neeraj Saini, Suman Kalyan Pradhan, Mintu Mondal, Mukul Kabir, Goutam Sheet
Abstract
The challenging task of scaling down the size of the power saving electronic devices can be accomplished by exploiting the spin degree of freedom of the conduction electrons in van der Waals (vdW) spintronic architectures built with 2D materials. One of the key components of such a device is a near-room temperature 2D ferromagnet with good metallicity that can generate a highly spin-polarized electronic transport current. However, most of the known 2D ferromagnets have either a very low-temperature ordering, poor conductivity, or low spin polarization. In this context, the ${\mathrm{Fe}}_{n}{\mathrm{GeTe}}_{2}$ (with $n\ensuremath{\ge}3$) family of ferromagnets stand out due to their near-room temperature ferromagnetism and good metallicity. We have performed spin-resolved Andreev reflection spectroscopy on ${\mathrm{Fe}}_{4}{\mathrm{GeTe}}_{2}$ (${T}_{\mathrm{Curie}}\ensuremath{\sim}273\phantom{\rule{0.16em}{0ex}}\mathrm{K}$) and demonstrated that the ferromagnet is capable of generating a very high transport spin polarization, exceeding $50%$. This makes ${\mathrm{Fe}}_{4}{\mathrm{GeTe}}_{2}$ a strong candidate for application in all-vdW power-saving spintronic devices.