Comment on ``Universal Spin-Flip Transition in Itinerant Antiferromagnets"

TL;DR

This paper challenges previous claims about spin-flip transitions in itinerant antiferromagnets, demonstrating that the canted antiferromagnetic state remains stable up to a critical field, aligning with localized antiferromagnet behavior.

Contribution

It provides a corrected analysis showing the canted state as the ground state in itinerant antiferromagnets under magnetic fields, contrary to prior assertions.

Findings

The canted state is the true ground state up to a critical field.

The normal state is restored at the critical field.

Results align with localized antiferromagnet behavior.

Abstract

In a recent paper [Phys. Rev. Lett. 91, 117201 (2003)], it is argued that an itinerant antiferromagnet in an external magnetic field undergoes a spin-flip transition, in marked contrast with the behavior of a localized antiferromagnet: for a weak magnetic field, the magnetization is parallel to the field, and flips to the perpendicular configuration at a critical value of the field. In this Comment we show that these conclusions are incorrect. The canted state (not considered in the Letter) is the antiferromagnetic ground state of the system up to a critical value of the field where the normal state is restored, in qualitative agreement with the behavior of the magnetization in a localized antiferromagnet.