Supreme enhancement of ferromagnetism in a spontaneous-symmetry-broken 2D nanomagnet

• Published in: Journal of physics. D, Applied physics Vol. 54; no. 10; pp. 105001 - 105008
• Main Authors: Kar, S, Nair, A K, Ray, S J
• Format: Journal Article
• Language: English
• Published: IOP Publishing 11.03.2021
• Subjects: 2D magnet; ferromagnetism; spintronics
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/1361-6463/abc64c

The ability to tune and control the magnetic phases of two-dimensional (2D) nanomagnets at room temperature is indispensable for the development of future spintronics and low-dimensional spin circuits. In this work, a first-principles-based investigation combined with a Monte Carlo simulation based on a 2D Ising model is used to investigate the electronic and magnetic behaviour of a recently discovered 2D material, Cr2Ge2Se6 over a large range of strain and electric field strength. This material offers ferromagnetic → antiferromagnetic and semiconductor → metallic phase transitions in different regimes. In the presence of strain, a colossal enhancement of the critical temperature (Tc) is observed, from 149 K to 885 K. The application of an electric field allows a further enhancement of the Tc to a value of 919 K, offering a supreme enhancement (~517%), compared to its natural condition. The origin of this behavior can be traced to a super-exchange interaction between the Cr and Se atoms and the intrinsic magnetic anisotropy of Cr2Ge2Se6. The presence of external stimuli engenders spontaneous symmetry breaking with an enhanced magnetic moment (~4.36 μB/Cr atom), a significant intrinsic spin polarisation (~100%) in a half-metallic regime, and a very high critical temperature. The insights of the current investigation could be useful for future developments in multi-stimuli-assisted room-temperature ferromagnetism and electronic phase control, which are of great significance for future magneto-electronic applications.