Magentic Ordering under Hydrostatic Pressure in Doped Spin Gap Systems ACu$_{1-x}$Mg$_x$Cl$_3$: A$=$Tl and K

TL;DR

This study investigates how hydrostatic pressure influences magnetic phase transitions in doped spin gap systems TlCu$_{0.988}$Mg$_{0.012}$Cl$_3$ and KCu$_{0.973}$Mg$_{0.027}$Cl$_3$, revealing impurity-induced orderings and phase transitions to antiferromagnetic states.

Contribution

It provides new insights into pressure-induced magnetic phase transitions in doped spin gap materials, highlighting the crossover from impurity-induced order to uniform antiferromagnetism.

Findings

Ordering temperature $T_N$ increases with pressure.

Phase transition to uniform antiferromagnetic phase occurs at ~1.3 kbar.

Pressure closes the triplet gap in the dimers.

Abstract

Magnetic phase transitions under hydrostatic pressures in spin gap systems TlCu$_{0.988}$Mg$_{0.012}$Cl$_3$ and KCu$_{0.973}$Mg$_{0.027}$Cl$_3$ were investigated by magnetization measurements. The present doped systems exhibit impurity-induced magnetic orderings. With increasing pressure, ordering temperature $T_{\rm N}$ increases. With a further increase in pressure, the present systems undergo phase transitions to uniform antiferromagnetic phases due to the closing of the triplet gap in the intact dimers. The crossover from the impurity-induced ordered phase to the uniform antiferromagnetic phase occurs at $P \simeq 1.3$ kbar for TlCu$_{0.988}$Mg$_{0.012}$Cl$_3$.