# Tricritical behavior of two-dimensional intrinsic ferromagnetic semiconducting CrGeTe3

## TL;DR

This study investigates the critical magnetic behavior of 2D ferromagnetic semiconductor CrGeTe3, demonstrating it follows a tricritical mean-field model and suggesting a transition from 2D to 3D magnetism near a tricritical point.

## Contribution

The paper provides experimental evidence that CrGeTe3's magnetic phase transition conforms to a tricritical mean-field model, indicating a 2D to 3D magnetic transition near a tricritical point.

## Key findings

- CrGeTe3 exhibits tricritical mean-field critical exponents.
- Magnetic phase transition occurs near 67.9 K.
- Transition from 2D to 3D magnetism is near a tricritical point.

## Abstract

CrGeTe3 recently emerges as a new two-dimensional (2D) ferromagnetic semiconductor that is promising for spintronic device applications. Unlike CrSiTe3 whose magnetism can be understood using the 2D-Ising model, CrGeTe3 exhibits a smaller van der Waals gap and larger cleavage energy, which could lead to a transition of magnetic mechanism from 2D to 3D. To confirm this speculation, we investigate the critical behavior CrGeTe3 around the second-order paramagnetic-ferromagnetic phase transition. We obtain the critical exponents estimated by several common experimental techniques including the modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis, which show that the magnetism of CrGeTe3 follows the tricritical mean-field model with the critical exponents \b{eta}, {\gamma}, and {\delta} of 0.240, 1.000, and 5.070, respectively, at the Curie temperature of 67.9 K. We therefore suggest that the magnetic phase transition from 2D to 3D for CrGeTe3 should locate near a tricritical point. Our experiment provides a direct demonstration of the applicability of the tricritical mean-field model to a 2D ferromagnetic semiconductor.