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arXiv · 1706.03239

Tricritical behavior of two-dimensional intrinsic ferromagnetic semiconducting CrGeTe3

G. T. Lin·H. L. Zhuang·X. Luo·B. J. Liu·F. C. Chen·J. Yan·Y. Sun·J. Zhou·W. J. Lu·P. Tong·Z. G. Sheng·Z. Qu·W. H. Song·X. B. Zhu·Y. P. Sun
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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.

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G. T. Lin, H. L. Zhuang, X. Luo, B. J. Liu, F. C. Chen, J. Yan, Y. Sun, J. Zhou, W. J. Lu, P. Tong, Z. G. Sheng, Z. Qu, W. H. Song, X. B. Zhu, Y. P. Sun. 2017-06-10. Tricritical behavior of two-dimensional intrinsic ferromagnetic semiconducting CrGeTe3. https://doi.org/10.1103/physrevb.95.245212

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