Unconventional relaxation in antiferromagnetic CoRh$_2$O$_4$ nanoparticles

TL;DR

This study investigates magnetic relaxation in antiferromagnetic CoRh₂O₄ nanoparticles at very low temperatures, revealing unconventional relaxation behavior influenced by surface effects as particle size decreases.

Contribution

It uncovers unique relaxation phenomena in CoRh₂O₄ nanoparticles, highlighting the role of surface exchange anisotropy in antiferromagnetic relaxation.

Findings

Unconventional magnetic relaxation observed at 2 K.

Surface exchange anisotropy increases with decreasing particle size.

Relaxation behavior differs from typical antiferromagnetic systems.

Abstract

Magnetic relaxation in antiferromagnetic CoRh$_2$O$_4$ nanoparticles is investigated at 2 K by cooling the sample from a temperature (70 K) well above the antiferromagnetic ordering temperature at 27 K, following zero field cooled (ZFC) and field cooled (FC) process. In ZFC process, the sample at 2 K is subsequently followed by magnetic field on and off sequences, whereas in FC process the cooling field is made off during measurement of remanent magnetization as a function of time. The experiments suggest an unconventional relaxation behaviour in the system, as an effect of increasing surface exchange anisotropy with decreasing the size of antiferromagnetic nanoparticles.