Use of conventional electrochemical techniques to produce crystalline FeRh alloys induced by Ag seed layer

• Published in: Journal of alloys and compounds 2013-10, Vol.573, p.37-42
• Main Authors: Noce, R.D., Benedetti, A.V., Passamani, E.C., Kumar, H., Cornejo, D.R., Magnani, M.
• Format: Article
• Language: English
• Subjects: Ag seed layer; Alloys; Brasses; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystalline state (including molecular motions in solids); Deposition; Diamagnetism, paramagnetism and superparamagnetism; Diffraction; Electrodeposition; Electrodeposition, electroplating; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; FeRh alloys; Ferrous alloys; Galvanic displacement; Intermetallics; Iron; Magnetic properties and materials; Magnetization; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Mossbauer effect; Physics; Seeds; Solid-solid transitions; Specific phase transitions; Structure of solids and liquids; crystallography; Theory of crystal structure, crystal symmetry; calculations and modeling
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.03.282

•Production of FeRh alloys by electrodeposition.•Use of Ag seed layer causes crystallization in electrodeposited Fe20Rh80 alloy.•Mössbauer spectroscopy indicates that the FeRh/Ag alloy has a long range atomic order structure. By combining galvanic displacement and electrodeposition techniques, an ordered Fe20Rh80 structure deposited onto brass was investigated by X-ray diffractometry, Mössbauer spectroscopy and magnetization measurements. Mössbauer and X-ray diffraction analyses suggest that the Fe–Rh alloy directly electrodeposited onto brass displays a nanocrystalline state while a similar alloy deposited onto Ag/brass shows a faced centered cubic-like structure, with dendrites-like features. These results directly indicate that the presence of Ag seed layer is responsible for the Fe–Rh alloy crystallization process. In addition, room temperature Mössbauer data indicate firstly paramagnetic states for two Fe-species. In the dominant Fe-species (major fraction of the Mössbauer spectra), Fe atoms are situated at a cubic environment and it can be attributed to the γ-Fe20Rh80 alloy based on their hyperfine parameters. In the second species, Fe atoms are placed in a non-local symmetry, which can be related to Fe atoms at the grain boundaries or/and Fe small clusters. These Fe-clusters are in superparamagnetic state at room temperature, but they may be ordered below 45K, as suggested by magnetization data.