Tuning the Magnetic Properties of Two-Dimensional MXenes by Chemical Etching.

Kemryn Allen-Perry,Bhoj Gautam,Lewis Reynolds,Shubo Han,Daniel E Autrey,Danielle Keith,Weston Straka

doi:10.3390/ma14030694

Abstract

Two-dimensional materials based on transition metal carbides have been intensively studied due to their unique properties including metallic conductivity, hydrophilicity and structural diversity and have shown a great potential in several applications, for example, energy storage, sensing and optoelectronics. While MXenes based on magnetic transition elements show interesting magnetic properties, not much is known about the magnetic properties of titanium-based MXenes. Here, we measured the magnetic properties of Ti3C2Tx MXenes synthesized by different chemical etching conditions such as etching temperature and time. Our magnetic measurements were performed in a superconducting quantum interference device (SQUID) vibrating sample. These data suggest that there is a paramagnetic-antiferromagnetic (PM-AFM) phase transition and the transition temperature depends on the synthesis procedure of MXenes. Our observation indicates that the magnetic properties of these MXenes can be tuned by the extent of chemical etching, which can be beneficial for the design of MXenes-based spintronic devices.

Highlights

Since the first reported synthesis of single-layer graphene by the mechanical exfoliation of graphite in 2004, there has been tremendous research interest in the chemical, electronic and physical properties of two-dimensional (2D) materials [1]
We report the synthesis of Ti3 C2 Tx MXenes, which are robust to oxidation [8], using a milder lithium fluoride (LiF)/hydrochloric acid (HCl) solution and investigate the magnetic properties
After LiF/HCl etching at room temperature (Batch 1), the (002) peak broadened and shifted towards a smaller angle (7.2◦ ) compared with the unetched Ti3 AlC2, indicating that Al was replaced by –F or –OH moieties especially near the surface region [43,46]

Summary

Introduction

Since the first reported synthesis of single-layer graphene by the mechanical exfoliation of graphite in 2004, there has been tremendous research interest in the chemical, electronic and physical properties of two-dimensional (2D) materials [1]. In 2011, it was first reported that 2D nanosheets of Ti3 C2 could be obtained by chemically etching the aluminum layer from Ti3 AlC2 MAX phase materials with hydrofluoric acid [2]. These materials were referred to as MXenes due to their similar electronic properties to graphene. The MXene general formula may be denoted as Mn+1 Xn Tx. To date, approximately 20 single-transition metal MXenes and 15 ordered double-transition metal. The optical [24,25] and electronic [11,26,27] properties of MXenes, the magnetic properties of these materials for spintronic application are relatively unexplored [21,28]

Methods

Results

Conclusion