Materials Chemistry and Physics 260 (2021) 124112 Available online 30 November 2020 0254-0584/© 2020 Elsevier B.V. All rights reserved. Spontaneous morphology and phase modifcation driven by sequence of deposition in superconducting Ni–Bi bilayers Liying Liu a , Yutao Xing b, * , I.L.C. Merino a , M.D.R. Henriques b , Mauro D´ oria c , I.G. Sol´ orzano d , E. Baggio-Saitovitch a a Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, 22290-180, Brazil b Laborat´ orio de Microscopia Eletrˆ onica de Alta Resoluç˜ ao, Centro de Caracterizaç˜ ao Avançada para Indústria de Petr´ oleo (LaMAR/CAIPE), Universidade Federal Fluminense, Niter´ oi, 24210-346, Brazil c Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil d DEQM, Pontifícia Universidade Cat´ olica do Rio de Janeiro, Rio de Janeiro, 22451-900, Brazil HIGHLIGHTS G R A P H I C A L ABSTRACT • Sequence of deposition induces modif- cation of morphology in Ni–Bi bilayers. • Intermetallic NiBi 3 phase is formed in both samples. • For the reaction Ni+3Bi.→NiBi 3 , the volumes have the relation: V NiBi 3 <V Bi < V Ni + V Bi. • NiBi 3 undergoes distinctly different nucleation and growth processes in the two samples. • Both Ni–Bi bilayers are superconducting with T c ~4.0 K. A R T I C L E INFO Keywords: Ni–Bi bilayers Superconductivity Phase modifcation Nucleation and growth ABSTRACT We report how the sequence of deposition of Ni and Bi affects the fnal morphology of Ni–Bi bilayers. Two samples have been prepared by sputtering with the same thickness of Ni (4 nm) and Bi (40 nm) but reversed sequence of deposition. The sample with Bi deposited frst formed a smooth layer of NiBi 3 intermetallic, while the sample Ni deposited frst formed mainly NiBi 3 nanoparticles with its out-of-plane dimensions bigger than the thickness of the total deposited bilayer. The NiBi 3 phase in the two samples results from differing nucleation and growth processes leading to differing morphologies. The volume of NiBi 3 is smaller than the pure Bi volume needed for the reaction and this volume contraction is a thermodynamic factor that favors the NiBi 3 formation. Both samples are superconducting with the critical temperature T c of ~4.0 K. The Ni–Bi system offers an example of the formation of a superconducting compound under a volume contraction of its constituents, thus being of interest for both researchers in physics and material sciences. * Corresponding author. E-mail address: xy@id.uff.br (Y. Xing). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys https://doi.org/10.1016/j.matchemphys.2020.124112 Received 17 June 2020; Received in revised form 12 September 2020; Accepted 27 November 2020