\muSR-dtected Soft mode toward a Possible Phase Transition in disordered spin gap system (CH3)2CHNH3-Cu(ClxBr1-x)3

TL;DR

This study investigates a disordered spin-gap system using muon spin relaxation, revealing a potential phase transition driven by soft magnetic modes as temperature decreases.

Contribution

The paper provides microscopic evidence of soft magnetic modes indicating a possible phase transition in a disordered spin-gap system, expanding understanding of its magnetic ground state.

Findings

Gapless behavior in certain compositions.

Observation of decreasing fluctuation frequency with temperature.

Evidence of a magnetic ground state.

Abstract

Measurements of macroscopic properties have indicated that the bond-disordered spin-gap system (CH3)2CHNH3-Cu(ClxBr1-x)3 is gapless when x is between 0.44 and 0.87. Using muon spin relaxation to investigate microscopic properties of sample with x=0.35, we observed a dynamical spin fluctuation, whose characteristic frequency decreases with decreasing temperature, indicating a magnetic ground state.