Observing the magnetic phase transition in a quasi-2D material: Fe$_{\mathrm{\mathbf{3}}}${GeTe}$_{\mathrm{\mathbf{2}}}$

As a quasi-2D magnetic material, Fe$_{\mathrm{3}}$GeTe$_{\mathrm{2}}$ was recently found having an antiferromagnetic ground state at low temperature but showing competition between antiferromagnetic and ferromagnetic states above 152K. The ferromagnetic ab layers of Fe$_{\mathrm{3}}$GeTe$_{\mathrm{2}}$ actually order antiferromagnetically along the c-axis below 152 K. The complicated phase transitions, the competition between phases and the evolution of the anitiferromagnetic phase were confirmed using in-situ variable temperature magnetic force microscopy. Fe$_{\mathrm{3}}$GeTe$_{\mathrm{2}}$ shares many common features with pnictide superconductors and may be a promising system in which to search f or unconventional superconductivity. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.