In this work, we demonstrate that cutting diamond crystals with a laser (532~nm wavelength, 0.5~mJ energy, 200~ns pulse duration at 15~kHz) produces a ≲20nm thick surface layer with magnetic order at room temperature. We have measured the magnetic moment of five natural and six CVD diamond crystals of different size, nitrogen content and surface orientations with a SQUID magnetometer. A robust ferromagnetic response at 300~K is observed only for crystals that were cut with the laser along the (100) surface orientation. The magnetic signals are much weaker for the (110) and negligible for the (111) orientations. We attribute the magnetic order to the disordered graphite layer produced by the laser at the diamond surface. The ferromagnetic signal vanished after chemical etching or after moderate temperature annealing. The obtained results indicate that laser treatment of diamond may pave the way to create ferromagnetic spots at its surface.
@article{arxiv.2112.03671,
title = {Nanometers-thick Ferromagnetic Surface Produced by Laser Cutting of Diamond},
author = {Annette Setzer and Pablo D. Esquinazi and Sergei Buga and Milena T. Georgieva and Tilo Reinert and Tom Venus and Irina Estrela-Lopis and Andrei Ivashenko and Maria Bondarenko and Winfried Böhlmann and Jan Meijer},
journal= {arXiv preprint arXiv:2112.03671},
year = {2022}
}