Induced quantum magnetism on a triangular lattice of non-Kramers ions in PrMgAl11O19

TL;DR

This study investigates the quantum magnetic behavior of PrMgAl11O19, revealing induced quantum magnetism on a triangular lattice with strong anisotropy and no long-range order down to very low temperatures, modeled as a quantum Ising system.

Contribution

It provides the first detailed experimental analysis of induced quantum magnetism in a non-Kramers ion triangular lattice, proposing a quantum Ising model with an intrinsic transverse field.

Findings

Strong Ising-like magnetic anisotropy observed.

No long-range magnetic order down to 0.4 K.

Quantum magnetism induced by magnetic interactions.

Abstract

We report the magnetic properties of the quantum triangular lattice antiferromagnet (TLAF) PrMgAl11O19 through magnetization and specific heat measurements. Strong magnetic anisotropy indicates the realization of an Ising-like magnetism in PrMgAl11O19 single crystal while no long-range magnetic ordering is realized down to 0.4 K. The splitting of the low-lying quasi-doublet into two singlets suggested by experimental data, is consistent with an effective pseudospin-1/2 scenario. The observed gapless excitations in zero field are attributed to induced quantum magnetism, they would be induced by magnetic interactions of an energy scale comparable with the splitting between the two singlets. Based on these results, we modeled the magnetic ground state of PrMgAl11O19 by a quantum Ising magnet with an intrinsic transverse field rather than a quantum spin liquid (QSL). In addition, our data show a non-monotonous response of the low-temperature specific heat to the external fields revealing a complex interplay between intrinsic and external magnetic fields.