Field-induced magnetic order in DyTa$_7$O$_{19}$ with two-dimensional pseudospin-$\frac{1}{2}$ triangular lattice

TL;DR

This study investigates DyTa$_7$O$_{19}$, a two-dimensional triangular lattice antiferromagnet, revealing a field-induced up-up-down magnetic order driven by dipolar interactions, with potential implications for quantum magnetic states.

Contribution

It provides the first comprehensive magnetic characterization of DyTa$_7$O$_{19}$, demonstrating a field-induced magnetic order explained by dipolar interactions in a frustrated lattice.

Findings

Field-induced magnetic order with net magnetization of M_s/3 below 0.14 K.

Magnetic order driven by dipole-dipole interactions among Ising-like Dy$^{3+}$ spins.

Theoretical calculations match experimental phase diagram based on dipolar interactions.

Abstract

The magnetic ground state of geometrically frustrated antiferromagnet attracts great research interests due to the possibility to realize novel quantum magnetic state such as a quantum spin liquid. Here we present a comprehensive magnetic characterization of DyTa$_7$O$_{19}$ with ideal two-dimensional triangular lattice. DyTa$_7$O$_{19}$ exhibits $c$-axis single-ion magnetic anisotropy. Although long-range magnetic order is not observed down to 100 mK under zero field, by applying a small magnetic field ($\sim$0.1 T), a magnetically ordered state with net magnetization of $M_s$/3 below $T_m$=0.14 K is identified ($M_s$ denotes the saturated magnetization). We argue that this state is an up-up-down magnetic structure phase driven by the dipole-dipole interactions between Ising-like spins of Dy$^{3+}$ in a two-dimensional triangular lattice, since its ordering temperature and temperature-field phase diagram can be well explained by the theoretical calculations based on dipolar interactions. DyTa$_7$O$_{19}$ could be viewed as a rare material platform that realizing pure Ising-like dipolar interaction in a geometrically frustrated lattice.