# Spin-wave phase inverter upon a single nanodefect

## TL;DR

This paper demonstrates a simple, tunable spin-wave phase inverter using a nanogroove in a magnonic waveguide, advancing miniaturized magnonic device design by controlling phase shifts with geometric and magnetic parameters.

## Contribution

It introduces a novel on-chip spin-wave phase shifter based on a single nanogroove, enabling broad tunability and integration into magnonic circuits.

## Key findings

- Achieved continuous phase tuning by varying groove depth and magnetic field.
- Experimentally demonstrated complete phase inversion.
- Identified the mechanism involving geometrical defect and reduced group velocity.

## Abstract

Local modification of magnetic properties of nanoelements is a key to design future-generation magnonic devices, in which information is carried and processed via spin waves. One of the biggest challenges here is to fabricate simple and miniature phase-controlling elements with broad tunability. Here, we successfully realize such spin-wave phase shifter upon a single nanogroove milled by focused ion beam in a Co-Fe microsized magnonic waveguide. By varying the groove depth and the in-plane bias magnetic field we continuously tune the spin-wave phase and experimentally evidence a complete phase inversion. The microscopic mechanism of the phase shift is based on the combined action of the nanogroove as a geometrical defect and the lower spin-wave group velocity in the waveguide under the groove where the magnetization is reduced due to the incorporation of Ga ions during the ion-beam milling. The proposed phase shifter can easily be on-chip integrated with spin-wave logic gates and other magnonic devices. Our findings are crucial for designing nano-magnonic circuits and for the development of spin-wave nano-optics.