Tungsten-encapsulated gadolinium nanoislands with enhanced magnetocaloric response

• Published in: Applied physics letters Vol. 111; no. 1
• Main Authors: Logan, J. M., Rosenmann, D., Sangpo, T., Holt, M. V., Fuesz, P., McNulty, I.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 03-07-2017; American Institute of Physics (AIP)
• Subjects: Applied physics; Coercivity; Crystal structure; Drying; Encapsulation; Gadolinium; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Islands; magnetic entropy; Magnetic properties; Magnetism; magnetocaloric effect; MATERIALS SCIENCE; nanoislands; nanostructuring; Organic chemistry; Remanence; Sapphire; Substrates; Temperature dependence; Thin films; Tungsten
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4990388

We report a method for growing chemically pure, oxide-free, air-stable Gd nanoislands with enhanced magnetic properties. These nanoislands are grown by solid-state dewetting and are fully encapsulated in tungsten such that they remain stable in ambient environments. They display good crystalline properties with hexagonally close-packed crystal structure and strong preferential orientation. We show that the choice of substrate strongly affects their shape, crystal orientation, and magnetic properties. The temperature-dependent magnetic coercivity and remanence of the Gd islands can vary by as much as a factor of three depending on the substrate used. The magnetocaloric properties of Gd islands grown on a sapphire substrate exceed those of high-quality Gd thin films.