# Interplay of magnetization dynamics with microwave waveguide at cryogenic temperatures

## TL;DR

This study investigates magnetization dynamics at cryogenic temperatures in a hybrid system combining a magnetic film and a superconducting microwave waveguide, revealing how superconductivity influences magnetic resonance properties.

## Contribution

It introduces a comprehensive analysis method for magnetic parameters and anisotropies in a cryogenic hybrid system, highlighting the impact of superconducting states on magnetization dynamics.

## Key findings

- Resonance spectrum observed across wide magnetic field range.
- Waveguide-induced magnetic anisotropies detected.
- Superconducting critical state significantly affects resonance spectrum.

## Abstract

In this work, magnetization dynamics is studied at low temperatures in a hybrid system that consists of thin epitaxial magnetic film coupled with superconducting planar microwave waveguide. The resonance spectrum was observed in a wide magnetic field range, including low fields below the saturation magnetization and both polarities. Analysis of the spectrum via a developed fitting routine allowed to derive all magnetic parameters of the film at cryogenic temperatures, to detect waveguide-induced uniaxial magnetic anisotropies of the first and the second order, and to uncover a minor misalignment of magnetic field. A substantial influence of the superconducting critical state on resonance spectrum is observed and discussed.