Role of Dy on the magnetic properties of orthorhombic DyFeO3

TL;DR

This study investigates the magnetic and structural properties of DyFeO3, revealing differences between powder and single crystal forms, including modified spin reorientation and incommensurate Dy ordering at low temperatures.

Contribution

It provides a detailed neutron diffraction and magnetometry analysis of DyFeO3, highlighting how powder and single crystal forms differ in magnetic behavior and structure.

Findings

Powder DyFeO3 shows a modified spin reorientation.

Dy ordering in powder is incommensurate with a ~58 unit cell periodicity.

Magnetic space groups differ between powder and single crystal.

Abstract

Orthoferrites are a class of magnetic materials with a magnetic ordering temperature above 600 K, predominant G-type antiferromagnetic ordering of the Fe-spin system and, depending on the rare-earth ion, a spin reorientation of the Fe spin taking place at lower temperatures. DyFeO3 is of particular interest since the spin reorientation is classified as a Morin transition with the transition temperature depending strongly on the Dy-Fe interaction. Here, we report a detailed study of the magnetic and structural properties of microcrystalline DyFeO3 powder and bulk single crystal using neutron diffraction and magnetometry between 1.5 and 450 K. We find that, while the magnetic properties of the single crystal are largely as expected, the powder shows strongly modified magnetic properties, including a modified spin reorientation and a smaller Dy-Fe interaction energy of the order of 10 {\mu}eV. Subtle structural differences between powder and single crystal show that they belong to distinct magnetic space groups. In addition, the Dy ordering at 2 K in the powder is incommensurate, with a modulation vector of 0.0173(5) c*, corresponding to a periodicity of ~58 unit cells.