Interwire and Intrawire Magnetostatic Interactions in Fe‐Au Barcode Nanowires with Alternating Ferromagnetically Strong and Weak Segments

Abstract

Metallic barcode nanowires (BNWs) composed of repeating heterogeneous segments fabricated by template‐assisted electrodeposition can offer extended functionality in magnetic, electrical, mechanical, and biomedical applications. The authors consider such nanostructures as a 3D system of magnetically interacting elements with magnetic behavior strongly affected by complex magnetostatic interactions. This study discusses the influence of geometrical parameters of segments on the character of their interactions and the overall magnetic behavior of the array of BNWs having alternating magnetization, because the Fe and Au segments are made of Fe‐Au alloys with high and low magnetizations. By controlling the applied current densities and the elapsed time in the electrodeposition, the dimension of the Fe‐Au BNWs can be regulated. This study reveals that the influence of the length of magnetically weak Au segments on the interaction field between nanowires is different for samples with magnetically strong 100 and 200 nm long Fe segments using the first‐order reversal curve (FORC) diagram method. With the help of micromagnetic simulations, three types of magnetostatic interactions in the BNW arrays are discovered and analy. This study demonstrates that the dominating type of interaction depends on the geometric parameters of the Fe and Au segments and the interwire and intrawire distances.

Au–Pd Barcode Nanowires with Tailored Lattice Parameters and Segment Lengths for Catalytic Applications

“…Nanostructures incorporating multimetallic components have been a subject of considerable interest due to their unique properties and outstanding performance arising from the synergistic interaction between the metal components. − The prominent examples of such nanostructures based on two or more metals could include nanoalloys, , heterostructures, such as core–shell nanoparticles, , barcode nanorods, and nanowires. − …”

Exploring the Magnetic Properties of Individual Barcode Nanowires using Wide‐Field Diamond Microscopy

“…Combining these effects was necessary to explain the overall reduced field strength compared with the OOMMF result and the hole-like features appearing inside the dipole. Based on a comparison between the experimental and simulation results, we were able to extract data on the saturation magnetization of individual nanowires that are compatible with bulk values, i.e., M s = 1.7 × 10 6 A m −1 for Fe [24] and M s = 1.4 × 10 6 A m −1 for Co, [2,41] but varies moderately depending on the wire. More information regarding the simulation is provided in the Supplementary Materials.…”

“…However, the magnetic behavior of individual nanowires can differ from that of the ensemble owing to the magnetostatic interactions between the nanowires. [ 24 ] In addition, even when made concurrently, nanowires can have non‐uniform diameters and lengths. As a result, measurements on the nanowire arrays provide statistically obtained average magnetic property values, although each nanowire may have a different value.…”

“…Previous studies have also reported reduced M s values for single nanowires. [2,24,42] Note that when we change the two free parameters, we make sure they stay within the range of possible values, which can be determined either from a separate measurement, e.g., wire diameter, or from references, e.g., bulk saturation magnetization values. Despite these constraints, however, we acknowledge that possible subsets of the two parameters with minor variations are possible.…”