Using the CIQTEK Scanning NV Microscope (SNVM), the team successfully demonstrated room-temperature ferromagnetism in the semiconducting material MnS₂. The findings were published in the Journal of the American Chemical Society (JACS) under the title “Experimental Evidence of Room-Temperature Ferromagnetism in Semiconducting MnS₂.”

https://pubs.acs.org/doi/10.1021/jacs.5c10107

Pioneering Discovery in 2D Ferromagnetic Semiconductors

The discovery of 2D ferromagnetic semiconductors has raised great expectations for advancing Moore’s Law and spintronics in memory and computation. However, most explored 2D ferromagnetic semiconductors exhibit Curie temperatures far below room temperature. Despite theoretical predictions of many potential room-temperature 2D ferromagnetic materials, the experimental synthesis of ordered and stable metastable structures remains a formidable challenge.

In this study, the researchers developed a template-assisted chemical vapor deposition (CVD) method to synthesize layered MnS₂ microstructures within a ReS₂ template. High-resolution atomic characterizations revealed that the monolayer MnS₂ microstructure crystallized well in a distorted T-phase. The optical bandgap and temperature-dependent carrier mobility confirmed its semiconducting nature.

By combining vibrating sample magnetometry (VSM), electrical transport measurements, and micro-magnetic imaging using CIQTEK SNVM, the team provided solid experimental evidence of room-temperature ferromagnetism in MnS₂. Electrical transport measurements also revealed an anomalous Hall resistance component in the monolayer samples. Theoretical calculations further indicated that this ferromagnetism originates from short-range Mn–Mn interactions.

This work not only confirms the intrinsic room-temperature ferromagnetism of layered MnS₂ but also proposes an innovative approach for the growth of metastable functional 2D materials.

Two Key Breakthroughs

• Intrinsic Room-Temperature Ferromagnetism in MnS₂ Monolayers:
  The study experimentally demonstrates intrinsic room-temperature ferromagnetism in semiconducting MnS₂, resolving the long-standing conflict between semiconductivity and magnetism.

• Template-Assisted CVD Strategy for Metastable Ferromagnetic Microstructures:
  The developed synthesis strategy enables scalable fabrication of metastable ferromagnetic microstructures.

These advances establish MnS₂ as a model platform for 2D spintronics, offering a new pathway for engineering low-dimensional magnetic materials.

ChatGPT 说：

Figure 2: Micro-Region Magnetic Imaging

Figure 3: Electrical Transport Measurements

CIQTEK SNVM: Key Instrument Behind the Discovery

The CIQTEK Scanning NV Microscope (SNVM) played a crucial role in this research. Its high-precision nanoscale magnetic imaging capabilities were essential for visualizing and confirming the magnetic properties of MnS₂. This study highlights how CIQTEK's advanced scientific instruments are empowering frontier research in materials science and condensed matter physics.

This breakthrough not only drives progress in 2D material studies but also opens new opportunities for spintronics and next-generation memory technologies.

Experience CIQTEK SNVM

CIQTEK SNVM is a world-leading nanoscale magnetic field imaging system, offering:

• Temperature range: 1.8–300 K

• Vector magnetic field: 9/1/1 T

• Magnetic spatial resolution: 10 nm

• Magnetic sensitivity: 2 μT/Hz¹ᐟ²

Based on NV center-based optically detected magnetic resonance (ODMR) and atomic force microscopy (AFM) scanning imaging, the SNVM provides high spatial resolution, high magnetic sensitivity, multifunctional detection, and non-invasive measurement.

It is a powerful tool for magnetic domain characterization, antiferromagnetic imaging, superconductivity studies, and 2D magnetic materials research, enabling scientists to explore materials with high precision and confidence.

Recently, a team led by Wang Haomin from the Shanghai Institute of Microsystem and Information Technology of the Chinese Academy of Sciences made significant progress in studying the magnetism of zigzag graphene nanoribbons (zGNRs) using a CIQTEK Scanning Nitrogen-vacancy Microscope (SNVM).

Building on previous research, the team pre-etched hexagonal boron nitride (hBN) with metal particles to create oriented atomic trenches and used a vapor-phase catalytic chemical vapor deposition (CVD) method to controllably prepare chiral graphene nanoribbons in the trenches, obtaining ~9 nm wide zGNRs samples embedded in the hBN lattice. By combining SNVM and magnetic transport measurements, the team directly confirmed its intrinsic magnetism in experiments. This groundbreaking discovery lays a solid foundation for the development of graphene-based spin electronic devices. The related research findings, titled "Signatures of magnetism in zigzag graphene nanoribbons embedded in a hexagonal boron nitride lattice," have been published in the prestigious academic journal "Nature Materials".

Graphene, as a unique two-dimensional material, exhibits magnetic properties of p-orbital electrons that are fundamentally different from the localized magnetic properties of d/f orbital electrons in traditional magnetic materials, opening up new research directions for exploring pure carbon-based magnetism. Zigzag graphene nanoribbons (zGNRs), potentially possessing unique magnetic electronic states near the Fermi level, are believed to hold great potential in the field of spin electronics devices. However, detecting the magnetism of zGNRs through electrical transport methods faces multiple challenges. For instance, nanoribbons assembled from the bottom up are often too short in length to reliably fabricate devices. Additionally, the high chemical reactivity of zGNR edges can lead to instability or uneven doping. Furthermore, in narrower zGNRs, the strong antiferromagnetic coupling of edge states can make it difficult to detect their magnetic signals electrically. These factors hinder direct detection of the magnetism in zGNRs.

ZGNRs embedded in the hBN lattice exhibit higher edge stability and feature an inherent electric field, creating ideal conditions for detecting the magnetism of zGNRs. In the study, the team used CIQTEK's Room-Temperature SNVM to observe the magnetic signals of zGNRs directly at room temperature.

Figure 1: Magnetic measurement of zGNR embedded in a hexagonal boron nitride lattice using Scanning Nitrogen-vacancy Microscope

In electrical transport measurements, the fabricated approximately 9-nanometer-wide zGNR transistors demonstrated high conductivity and ballistic transport characteristics. Under the influence of a magnetic field, the device exhibited significant anisotropic magnetoresistance, with a magnetoresistance change of approximately 175 Ω at 4 K, a magnetoresistance ratio of about 1.3%, and this signal persisted even at temperatures as high as 350 K. Hysteresis was only observed under a magnetic field perpendicular to the plane of the zGNRs, confirming its magnetic anisotropy. Through analysis of the variation of magnetoresistance with tilting angle, the researchers found that the magnetic moment is perpendicular to the sample surface. Furthermore, the decrease in magnetoresistance with increasing source-drain bias and temperature revealed the interaction between magnetic response and charge transport and thermal vibrations.

Figure 2: Magnetic transport characteristics of 9-nanometer-wide zGNR devices embedded in hBN

This research, by combining Scanning Nitrogen-vacancy Microscope technology and transport measurements, directly confirmed the existence of intrinsic magnetism in hBN-embedded zGNRs for the first time, providing a possibility for controlling magnetism through an electric field. This work not only deepens the understanding of graphene's magnetic properties but also opens up new pathways for the development of spin electronic devices based on graphene.

Experience the Nano-scale Magnetic Imaging System

CIQTEK invites you to experience the Scanning Nitrogen-vacancy Microscope (SNVM) – a globally leading nano-scale magnetic field imaging system, operating at temperatures of 1.8~300 K with a vector magnetic field of 9/1/1 T, achieving a magnetic spatial resolution of 10 nm, and magnetic sensitivity of 2 μT/Hz1/2.

SNVM is a precision measurement instrument that combines Diamond Nitrogen-vacancy (NV) Optically Detected Magnetic Resonance (ODMR) technology with Atomic Force Microscopy (AFM) scanning imaging technology. It features high spatial resolution, high-sensitivity magnetic imaging, versatile detection capabilities, and non-invasive detection advantages, making it important in areas such as magnetic domain characterization, antiferromagnetic imaging, superconductor characterization, and research on two-dimensional magnetic materials.

Room temperature version of SNVM

Cryogenic version of SNVM