Anomalous spin dynamics in charge ordered, 'two-electron' doped manganite Ca_0.9Ce_0.1MnO_3 : consequence of a spin-liquid phase?

TL;DR

This study investigates charge-ordered Ca_0.9Ce_0.1MnO_3 and finds anomalous spin dynamics suggestive of a disorder-driven spin-liquid phase coexisting with charge order, revealed through EPR and magnetic measurements.

Contribution

It provides evidence for a spin-liquid phase in a charge-ordered manganite, highlighting the role of magnetic frustration and disorder in spin dynamics.

Findings

EPR linewidth shows anomalous temperature dependence in x=0.1 sample.

Evidence suggests coexistence of spin-liquid phase with charge order.

Magnetic frustration influences spin dynamics in the system.

Abstract

The 'two-electron' doped rare earth mangnites Ca_1-x Ce_x MnO_3 (x = 0.1,0.2) are probed using resistivity, ac susceptibility and electron paramagnetic resonance (EPR) measurements across their respective charge ordering (CO) temperatures T_CO = 173 K and 250 K. The EPR 'g' factor and intensity as well as the transport and magnetic behaviours of the two compositions are qualitatively similar and are as expected for CO systems. However, the EPR linewidth, reflective of the spin dynamics, for x = 0.1, shows a strongly anomalous temperature dependence, decreasing with decreasing temperature below T_CO in contrast with the sample with x = 0.2 and other CO systems. Keeping in view the evidence for magnetic frustration in the system, we propose that the anomalous temperature dependence of the linewidth is the signature of the occurrence of a disorder driven spin liquid phase, present along with charge ordering.