Interface driven magnetic interactions in nanostructured thin films of iron nanocrystallites embedded in a copper matrix

• Published in: Journal of applied physics 2015-05, Vol.117 (17)
• Main Authors: Desautels, R. D., Shueh, C., Lin, K.-W., Freeland, J. W., van Lierop, J.
• Format: Article
• Language: English
• Subjects: Alloys; Copper; Copper base alloys; Dichroism; Diffraction patterns; Experiments; Ferrous alloys; Ion beam assisted deposition; Ion beams; Ion bombardment; Magnetic permeability; Magnetism; MATERIALS SCIENCE; Morphology; Nanocrystals; Nuclear weapons; Reflectometry; Thin films; Transmission electron microscopy; X ray absorption
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4913752

We have fabricated thin films of iron nanocrystallites embedded in a copper matrix using a dual ion beam assisted deposition technique. A secondary End-Hall ion beam bombarded the iron atoms during deposition altering significantly the morphology of the films and allowing for control of the intermixing between iron and copper components. Cross-sectional transmission electron microscopy and x-ray reflectometry experiments indicated that the morphology of the films was that of iron nanocrystallites embedded in a copper matrix. Rietveld refinements of the diffraction pattern identified fcc-copper and amorphous iron. An increased amount of disorder was observed with a reduction in the amount of deposited iron from a 1:1 Fe:Cu ratio to 0.25:0.75 Fe:Cu ratio. Interfacial copper-iron alloys were identified by DC susceptibility experiments through their reduced TC,Alloy (370, 310, and 280 K) compared with that of bulk iron (∼1000 K). Element specific x-ray absorption and x-ray magnetic circular dichroism experiments were performed to identify the contributions to the magnetism from the iron and the copper-iron alloy.