In this article published in Physical Review Materials, the team led by Professor Vincent Jacques uses quantitative magnetic imaging to demonstrate that exfoliated CrTe2 thin flakes exhibit in-plane ferromagnetic order at room temperature. The results were enabled by the use of Qnami QuantileverMX probes.
The magnetization in micron-sized flakes could be assessed only by using NV Magnetometry techniques where non-invasive magnetic microscopy is combined with the high sensitivity and high spatial resolution of atomic size quantum sensors as Qnami QuantileverTMMX probes.
The team studied the magnetic order at room temperature in CrTe2 samples with different thicknesses. The orientation and the strength of the magnetization were derived by comparing the measured magnetic field maps (obtained with NV magnetometry) with the simulated ones.
The orientation of the magnetization was found to be perpendicular to the long axis of the samples, different from what the shape anisotropy would point to. This suggests the existence of a significant magnetocrystalline anisotropy in CrTe2 thin flakes, which had not been observed before.
The strength of the magnetization in thin flakes was found to be stable for thicknesses in a few tens of nanometers range. The stable value was measured as five times lower than in bulk crystal samples most probably due to a lower Curie temperature in thin flakes.
The authors conclude that their findings open opportunities to explore magnetic phase transitions in two dimensional magnetic systems, and to design spintronic devices based on van der Waals magnets.
Read the full article in Physical Review Materials.