Change in Magnetic Order in NiPS3 Single Crystals Induced by a Molecular Intercalation

TL;DR

This study demonstrates how molecular intercalation with pyridine molecules can reversibly modify the magnetic order in NiPS3 single crystals, revealing mechanisms for tuning magnetism in van der Waals materials for quantum device applications.

Contribution

It introduces a novel method of controlling magnetic order in NiPS3 via molecular intercalation, supported by experimental and theoretical analysis, advancing the understanding of magnetic tuning in vdW systems.

Findings

Intercalation alters lattice parameters and magnetic transition temperatures.

Reversible magnetic order changes are achieved through intercalation-deintercalation cycles.

Intercalant orientation affects thermal transport and magnetic anisotropy.

Abstract

Intercalation is a robust method for tuning the physical properties of a vast number of van der Waals (vdW) materials. However, the prospects of using intercalation to modify magnetism in vdWs systems and the associated mechanisms have not been investigated adequately. In this work, we modulate magnetic order in an XY antiferromagnet NiPS3 single crystals by introducing pyridine molecules into the vdWs gap under different thermal conditions. X-ray diffraction measurements indicated pronounced changes in the lattice parameter beta, while magnetization measurements at in-plane and out-of-plane configurations exposed reversal trends in the crystals Neel temperatures through intercalation-de-intercalation processes. The changes in magnetic ordering were also supported by three-dimensional thermal diffusivity experiments. The preferred orientation of the pyridine dipoles within vdW gaps was deciphered via polarized Raman spectroscopy. The results highlight the relation between the preferential alignment of the intercalants, thermal transport, and crystallographic disorder along with the modulation of anisotropy in the magnetic order. The theoretical concept of double-exchange interaction in NiPS3 was employed to explain the intercalation-induced magnetic ordering. The study uncovers the merit of intercalation as a foundation for spin switches and spin transistors in advanced quantum devices.