Magnetic structure and phase diagram of the Heisenberg-Ising spin chain antiferromagnetic PbCo$_{2}$V$_{2}$O$_{8}$

TL;DR

This study investigates the magnetic structure and phase diagram of PbCo$_2$V$_2$O$_8$, revealing complex phases and a novel field-induced phase, expanding understanding of Heisenberg-Ising spin chain materials.

Contribution

It introduces PbCo$_2$V$_2$O$_8$ as a new member of the Heisenberg-Ising chain family and reports its magnetic phases and a previously unobserved field-induced phase.

Findings

PbCo$_2$V$_2$O$_8$ exhibits complex magnetic phases.

Discovery of a new field-induced phase for H∥[110].

Properties are comparable to SrCo$_2$V$_2$O$_8$ and BaCo$_2$V$_2$O$_8$.

Abstract

The effective spin-1/2 antiferromagnetic Heisenberg-Ising chain materials, ACo$_2$V$_2$O$_8$, A = Sr, Ba, are a rich source of exotic fundamental phenomena and have been investigated for their model magnetic properties both in zero and non-zero magnetic fields. Here we investigate a new member of the family, namely PbCo$_2$V$_2$O$_8$. We synthesize powder and single crystal samples of PbCo$_2$V$_2$O$_8$ and determine its magnetic structure using neutron diffraction. Furthermore, the magnetic field/temperature phase diagrams for magnetic field applied along the c, a, and [110] crystallographic directions in the tetragonal unit cell are determined via magnetization and heat capacity measurements. A complex series of phases and quantum phase transitions are discovered that depend strongly on both the magnitude and direction of the field. Our results show that \pcvo is an effective spin-1/2 antiferromagnetic Heisenberg-Ising chain with properties that are in general comparable to those of SrCo$_2$V$_2$O$_8$ and BaCo$_2$V$_2$O$_8$. One interesting departure from the results of these related compounds, is however, the discovery of a new field-induced phase for the field direction $H\|$[110] which has not been previously observed.