Crystal structure

Optics

Physics

Hall effect

Chemistry

Materials science

Trigonal crystal system

Spintronics

Condensed matter physics

Phase (matter)

Monoclinic crystal system

Quantum mechanics

Curie temperature

Electrical resistivity and conductivity

Crystallography

Ferromagnetism

Anisotropy

Nature Electronics

Two-dimensional materials that are intrinsically ferromagnetic are crucial for the development of compact spintronic devices. However, most non-layered 2D magnets with a strong ferromagnetic order are difficult to synthesize. Here we show that the flakes of trigonal and monoclinic Cr5Te8 can be grown via a chemical vapour deposition method. Using magneto-optical and magnetotransport measurements, we show that both phases exhibit robust ferromagnetism with strong perpendicular anisotropy at thicknesses of a few nanometres. A high Curie temperature of up to 200 K can be obtained by manipulating the phase structure and thickness. We also observe a colossal anomalous Hall effect in the more structurally distorted monoclinic Cr5Te8, with an anomalous Hall conductivity of 650 Ω−1 cm−1 and anomalous Hall angle of 5%. Few-nanometre-thick flakes of trigonal and monoclinic Cr5Te8 can be grown using chemical vapour deposition, with the monoclinic phase exhibiting an anomalous Hall conductivity of 650 Ω–1 cm–1 and anomalous Hall angle of 5%.

Phase engineering of Cr5Te8 with colossal anomalous Hall effect