# Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic field

## TL;DR

This study investigates how magnetic fields influence the magnetic structures of rare-earth iron pnictide superconductors, revealing spin-flop transitions and the role of rare-earth layers in modulating iron layer magnetism.

## Contribution

It presents a detailed analysis of magnetic phase transitions in RFeAsO and RFe2As2 compounds under magnetic fields using a cluster self-consistent field method, highlighting the interplay between rare-earth and iron spins.

## Key findings

- Spin-flop transitions occur in both rare-earth and iron layers.
- Rare-earth layers modulate the magnetic behavior of iron layers.
- Critical magnetic fields for spin-flop transitions are identified.

## Abstract

The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution of magnetic structures on magnetic field in RFeAsO (R=Ce, Pr, Nd, Sm, Gd and Tb) and RFe2As2 (R=Eu) compounds. It is found that spin-flop transition occurs in both rare-earth and iron layers under magnetic field, in good agreement with the experimental results. The interplay between rare-earth and iron spins plays a key role in the magnetic-field-driven magnetic phase transition, which suggests that the rare-earth layers can modulate the magnetic behaviors of iron layers. In addition, the factors that affect the critical magnetic field for spin-flop transition are also discussed.