  Across the fields of magnetism, microelectronics, optics, and others,
engineered local variations in physical properties can yield groundbreaking
functionalities that play a crucial role in enabling future technologies.
Beyond binary modifications, 1D lateral gradients in material properties
(achieved by gradients in thickness, stoichiometry, temperature, or strain)
give rise to a plethora of new effects in thin film magnetic systems. However,
extending such gradient-induced behaviors to 2D is challenging to realize with
existing methods, which are plagued by slow processing speeds, dose
instabilities, or limitation to variation along one dimension. Here, we show
for the first time how commonplace direct-write laser exposure techniques,
initially developed for grayscale patterning of photoresist surfaces, can be
repurposed to perform grayscale direct-write laser annealing. With this
technique, we demonstrate the ease with which two-dimensional, continuous
variations in magnetic properties can be created at the mesoscopic scale in
numerous application-relevant materials, including ferromagnetic,
ferrimagnetic, and synthetic antiferromagnetic thin-film systems. The speed,
versatility, and new possibilities to create complex magnetic energy landscapes
offered by direct-write laser annealing opens the door to the lateral
modification of the magnetic, electronic, and structural properties of a
variety of thin films with an abundance of applications.
