Large-Area Synthesis of Ferromagnetic Fe 5- x GeTe 2 /Graphene van der Waals Heterostructures with Curie Temperature above Room Temperature

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 39; p. e2302387
• Main Authors: Lv, Hua, da Silva, Alessandra, Figueroa, Adriana I, Guillemard, Charles, Aguirre, Iván Fernández, Camosi, Lorenzo, Aballe, Lucia, Valvidares, Manuel, Valenzuela, Sergio O, Schubert, Jürgen, Schmidbauer, Martin, Herfort, Jens, Hanke, Michael, Trampert, Achim, Engel-Herbert, Roman, Ramsteiner, Manfred, Lopes, Joao Marcelo J
• Format: Journal Article
• Language: English
• Published: Germany 01-09-2023
• Subjects: Fe5−xGeTe2; van der Waals heterostructures; 2D spintronics; 2D magnets; van der Waals epitaxy; graphene
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202302387

Van der Waals (vdW) heterostructures combining layered ferromagnets and other 2D crystals are promising building blocks for the realization of ultracompact devices with integrated magnetic, electronic, and optical functionalities. Their implementation in various technologies depends strongly on the development of a bottom-up scalable synthesis approach allowing for realizing highly uniform heterostructures with well-defined interfaces between different 2D-layered materials. It is also required that each material component of the heterostructure remains functional, which ideally includes ferromagnetic order above room temperature for 2D ferromagnets. Here, it is demonstrated that the large-area growth of Fe
GeTe
/graphene heterostructures is achieved by vdW epitaxy of Fe
GeTe
on epitaxial graphene. Structural characterization confirms the realization of a continuous vdW heterostructure film with a sharp interface between Fe
GeTe
and graphene. Magnetic and transport studies reveal that the ferromagnetic order persists well above 300 K with a perpendicular magnetic anisotropy. In addition, epitaxial graphene on SiC(0001) continues to exhibit a high electronic quality. These results represent an important advance beyond nonscalable flake exfoliation and stacking methods, thus marking a crucial step toward the implementation of ferromagnetic 2D materials in practical applications.