A system for making a material having domains with insulated boundaries is provided. The system includes a droplet spray subsystem configured to create molten alloy droplets and direct the molten alloy droplets to a surface, a gas subsystem configured to introduce one or more reactive gases to an area proximate in-flight droplets. The one or more reactive gases creates an insulation layer on the droplets in flight such that the droplets form a material having domains with insulated boundaries.