Evidence for unidimensional low-energy excitations as the origin of persistent spin dynamics in geometrically frustrated magnets

TL;DR

This study investigates the persistent spin dynamics in the frustrated magnet CdHo2S4, revealing unidimensional low-energy excitations as the likely cause, supported by specific heat, magnetic, and muon spin relaxation data.

Contribution

It provides evidence that unidimensional excitations underlie persistent spin dynamics in a geometrically frustrated magnet, a novel insight into the magnetic behavior of such systems.

Findings

Magnetic ordering at Tc ~ 0.87 K in CdHo2S4

Similar magnetic excitation modes below and above Tc

Unidimensional excitations likely cause persistent spin dynamics

Abstract

We report specific heat, magnetic, and muon spin relaxation measurements performed on a polycrystalline sample of the normal spinel CdHo2S4. The rare-earth ions sit on a lattice of corner-sharing regular tetrahedra as in pyrochlore compounds. Magnetic ordering is detected at Tc ~ 0.87 K. From spin-lattice relaxation rate measurements on both sides of Tc we uncover similar magnetic excitation modes driving the so-called persistent spin dynamics at T < Tc. Unidimensional excitations are argued to be at its origin. Often observed spin loop structures are suggested to support these excitations. The possibility of a generic mechanism for their existence is discussed.