Electrodeposition Growth of Nanowire Arrays with Height Gradient Profiles for Microwave Device Applications

Abstract

A simple and nonexpensive adapted dip-coating technique is presented and used to fabricate arrays of magnetic nanowires with a linear varying height profile. This approach allows controlling the wire height from tenths of nanometers up to several micrometers. Furthermore, the main parameters of this height gradient can be controlled, such as the maximum wire height and the lateral span of the wire array, which can be predicted with excellent accuracy using a proposed analytical model. Moreover, we show that by sequential electrodeposition with dip-coating, arrays of these height varying wires can be grown. This technique represents a novel method to fill porous templates with controlled spatial growth, leading to the fabrication of novel structures and providing control over structural features on the nanoscale level. In particular, the use of these asymmetrically loaded magnetic nanowired substrates to obtain improved microwave nonreciprocal behavior is shown for a microwave phase shifter.

High-frequency ferromagnetic resonance of Co nanowire arrays

“…During the last decade ferromagnetic nanowire arrays have attracted much research attention in microwave applications , such as circulators, isolators , phase shifters , and noise suppressors . On the road towards high‐frequency and small‐size microwave devices, a ferromagnetic nanowire array embedded into porous template with a template‐assisted method is a promising candidate material, whose ferromagnetic resonance (FMR) is observed in the microwave frequency range without applying any external magnetic field.…”

Electrochemically Generated Gradients

“…Encinas and co‐workers used this method in 2011 to fabricate arrays of magnetic Ni nanowires with a gradient in length 74. The gradient was formed by gradual withdrawal of a vertically positioned commercial porous anodized alumina (Al 2 O 3 ) template with a thickness of 60 μm from the electrodeposition solution by draining the liquid with a syringe pump.…”

Spin waves and electromagnetic waves in magnetic nanowires

“…It exhibits a circulation at 29.2 GHz with insertion losses as low as À6 dB and isolation of 35 dB. An integrated self-biased planar microwave circuit on nanowire substrates was proposed (Carignan et al, 2009b;Carreón-González et al, 2011;Wang et al, 2012). A similar circulator concept was presented (Marson et al, 2007(Marson et al, , 2008).…”