# Longitudinal modes of spin fluctuations in iron-based superconductors

## TL;DR

This paper investigates the longitudinal spin fluctuation modes in iron-based superconductors using an effective magnetic model, revealing insights into their magnetic behavior near phase boundaries.

## Contribution

It provides a unified analysis of longitudinal spin modes in iron-based superconductors, especially near phase boundaries, enhancing understanding of their magnetic fluctuations.

## Key findings

- Longitudinal modes vary near phase boundaries.
- Results aid in identifying magnetic fluctuation nature.
- Analysis applies to collinear antiferromagnetic phase.

## Abstract

Iron-based superconductors can exhibit different magnetic ground states and are in a critical magnetic region where frustrated magnetic interactions strongly compete with each other. Here we investigate the longitudinal modes of spin fluctuations in an unified effective magnetic model for iron-based superconductors. We focus on the collinear antiferromagnetic phase (CAF) and calculate the behavior of the longitudinal modes when different phase boundaries are approached. The results can help to determine the nature of the magnetic fluctuations in iron-based superconductors.