Signatures of a spin-1/2 cooperative paramagnet in the diluted triangular lattice of Y$_2$CuTiO$_6$

TL;DR

This study provides experimental evidence of a disorder-driven dynamic cooperative paramagnet in a diluted triangular lattice spin-1/2 system, showing no magnetic order down to very low temperatures and indicating potential for disorder-stabilized quantum states.

Contribution

It demonstrates the presence of a dynamic cooperative paramagnet in Y$_2$CuTiO$_6$ with no magnetic freezing, supported by scaling analyses consistent with random singlet physics.

Findings

No magnetic order or spin freezing down to 50 mK

Scaling collapse of heat capacity and magnetization data

Suppression of freezing scale by over three orders of magnitude

Abstract

We present a combination of thermodynamic and dynamic experimental signatures of a disorder driven dynamic cooperative paramagnet in a 50% site diluted triangular lattice spin-1/2 system, Y$_2$CuTiO$_6$. Magnetic ordering and spin freezing are absent down to 50 mK, far below the Curie Weiss scale of ~-134 K. We observe scaling collapses of the magnetic field- and temperature-dependent magnetic heat capacity and magnetisation data, respectively, in conformity with expectations from the random singlet physics. Our experiments establish the suppression of any freezing scale, if at all present, by more than three orders of magnitude, opening a plethora of interesting possibilities such as disorder-stabilized long range quantum entangled ground states.