  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
$\lesssim 20~$nm 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.
