Geometric and size effects on the thermal conductivity of fishbone-like nickel nanowires

Abstract

Thermal conductivity at the nanoscale often deviates significantly from that of bulk materials due to the mean free path of heat carriers becoming comparable to the system's dimensions, which challenges traditional heat transfer models. While magnetic nanowires are widely employed in various applications, their thermal properties remain poorly understood. This study investigates the thermal conductivity of nickel nanowires with a fishbone-like structure, focusing on the influence of flank angles (45°, 90°, and 135°) and characteristic sizes. Our results show that thermal conductivity decreases with decreasing flank angle relative to the heat flow direction, with this effect becoming negligible as the wire width approaches the microscale. Additionally, the thermal conductivity demonstrates a stronger size dependence in nanowires with acute flank angles (45°) compared to those with obtuse angles (135°). These results experimentally demonstrate a coupled effect of flank angle and characteristic width on the thermal conductivity of fishbone-like nickel nanowires, providing new insights into geometry-dependent thermal transport and offering guidance for the structural design of efficient thermal management systems.