RT Journal Article T1 Atomistic mechanisms triggered by Joule heating effects in metallic Cu-Bi nanowires for spintronics A1 Guedeja-Marrón Gil, Alejandra A1 Beltrán Fínez, Juan Ignacio A1 Saura Múzquiz, Matilde A1 Perna, Paolo A1 Muñoz de Pablo, Maria del Carmen A1 Pérez García, Lucas A1 Varela Del Arco, María AB Joule heating may severely impact the response to electric current injection of nanomaterials for spintronics. Here, the effects of heating in Bi doped Cu nanowires, a system where 1% Bi doping promotes a giant spin Hall effect (SHE), are studied by in situ high resolution electron microscopy. High quality Bi-Cu nanowires are grown by room temperature electrodeposition. The large size of Bi cations precludes insertion into the dense Cu face-centered lattice. Still, homogeneous compositions up to a nominal 7% Bi are successfully obtained with thicknesses <100 nm and grain sizes in the micron longitudinal scale, coated by a native oxide. In situ injection of current promotes fast Bi segregation out of solution. Controlled in situ annealing shows that the onset for segregation starts above temperatures of 250 °C. Within minutes, Bi atoms diffuse to grain boundaries or to exposed surfaces, such as the nanowire tips. Monoatomic thick Bi ordered decorations appear, preferentially on surface planes of the (Formula presented.) type. Annealing at 400 °C promotes the growth of pure Bi nanocrystals, coherent with the underlying Cu matrix. Still, the intra-grain Bi concentration remains finite at values near 1%. Density-functional theory calculations show that small amounts of Bi atoms are stable as substitutional impurities, confirming the potential of this system as building block for future spintronic devices. PB Wiley SN 0935-9648 YR 2025 FD 2025-11-21 LK https://hdl.handle.net/20.500.14352/128253 UL https://hdl.handle.net/20.500.14352/128253 LA eng NO A. Guedeja‐Marrón, J. Ignacio Beltrán, M. Saura‐Múzquiz, P. Perna, M. Carmen Muñoz, L. Pérez, M. Varela, Advanced Materials 2025, e13602. NO © 2025 The Author(s).AD2D-UCM3101109595 (MAGWIRE) NO Ministerio de Ciencia e Innovación (España) NO Agencia Estatal de Investigación (España) NO European Commission NO Comunidad de Madrid DS Docta Complutense RD 2 dic 2025