Influence of surfactant Ag on the structure of annealing Ni70Co30/Cu multilayers by X-ray reflection anomalous fine structure and X-ray absorption spectroscopy

• Published in: Physica. B, Condensed matter Vol. 382; no. 1-2; pp. 193 - 200
• Main Authors: AN, Y. K, ZHANG, H. D, MAI, Z. H, DAI, B, CAI, J. W, WU, Z. H, ZHOU, H. T, LIU, T
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 15-06-2006
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Physics; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); X-ray diffraction and scattering; X-ray reflectometry; Annealing; FCC lattices; Nickel alloys; Multilayer; Doping; Interdiffusion; X-ray reflection anomalous fine structure; X-ray reflection; XRD; 78.70.Dm; Surfactants; Surfactant; 75.70.i; EXAFS; Interfaces; Fine structure; 61.10.Ht; Silver; Multilayers; X-ray absorption spectra; X-ray absorption spectroscopy; Copper; Cobalt alloys; Transition element alloys
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2006.02.017

We performed X-ray reflection anomalous fine structure and X-ray absorption spectroscopy measurements to investigate the influence of Ag as a surfactant on the annealing Ni70Co30/Cu multilayer for the first time. Interfacial intermixing and silver diffusion levels were quantified at the atomic level. During the deposition, a 6A thick intermixing region exists at the Cu/Ni70Co30 interface while the Ni70Co30/Cu interface is sharp for the un-doped and the Ag-doped multilayers. After 285 deg C annealing, the two multilayers display different thermal behaviors. Severe diffusion occurs at the Cu/Ni70Co30 and Ni70Co30/Cu interfaces of the un-doped multilayer. However, of these the Ag-doped multilayer do not change significantly, indicating that the addition of silver can suppress interfacial intermixing after annealing. The Ag atoms in the Ag-doped multilayer have diffused into some parts of Ni70Co30 layer while do not exist at the interfaces during the deposition. After 285 deg C annealing, the Ag atoms diffused into the whole Ni70Co30 layer as well as some parts of the Cu layer. The X-ray absorption spectroscopy measures show that Ni atoms and Cu atoms occupy the interfacial positions in the un-doped multilayer. The addition of silver also do not change the FCC lattice of Co, Ni and Cu, but decrease the amplitude of the Ni and the Co K edge EXAFS profiles, suggesting that Ag atoms do diffuse into the Ni70Co30 layer.