X-ray Microdiffraction Images of Antiferromagnetic Domain Evolution in Chromium

TL;DR

This study employs magnetic x-ray diffraction with focusing optics to image antiferromagnetic domains in chromium, revealing how domain walls influence the spin-flip transition and demonstrating the technique's ability to independently extract magnetic parameters.

Contribution

It introduces a method to image and analyze antiferromagnetic domains at the micron scale, providing new insights into domain wall effects during magnetic transitions.

Findings

Domain walls initiate the spin-flip transition during cooling.

Transition begins at domain walls and propagates inward.

Modulation-vector domains remain unchanged during transition.

Abstract

Magnetic x-ray diffraction combined with x-ray focusing optics is used to image individual antiferromagnetic spin density wave domains in a chromium single crystal at the micron scale. The cross section for non-resonant magnetic x-ray scattering depends on the antiferromagnetic modulation vector and spin polarization direction and allows these quantities to be extracted independently. The technique is used to show that the broadening of the nominally first order "spin-flip" transition at 123 K, at which the spins rotate by 90 deg., originates at the walls between domains with orthogonal modulation vectors. During cooling the transition begins at these walls and progresses inwards. The modulation-vector domains are themselves unchanged.