Searching for Altermagnetism in Vapor-Deposited Amorphous Thin Films

Altermagnetism is a recently-identified third phase of collinear magnetism, joining ferromagnetism and antiferromagnetism. The altermagnetic (AM) phase is similar to the antiferromagnetic phase in that it consists of alternating opposite spins and a resultant net zero magnetic moment. The AM phase differs in that it breaks time-reversal symmetry due to orbital ordering, which results in an alternating spin texture in momentum space as well as in real space. This breaking of time-reversal symmetry lends altermagnets a surprising number of predicted properties similar to those often observed in ferromagnets, including the anomalous Hall effect, giant-magnetoresistance, and spin-transfer torque. The effect of disorder on altermagnets is not yet known. We will report on our progress growing amorphous manganese telluride, a known altermagnet in the crystalline phase, using physical vapor deposition. We will discuss high resolution transmission electron microscopy results, which are used to verify the amorphicity of our samples, and magnetization, resistivity, and magnetotransport data, including Hall effect as a function of temperature, magnetic field, and composition. We will compare these to the compensated magnetism and anomalous Hall effect that are characteristics of the AM phase in crystalline MnTe.