Manganese thiophosphite joins 2-D materials club

Examples of materials measuring just a few atoms thick have been popping up so quickly in recent years that many categories of materials now have several members in the two-dimensional materials club. The list includes organics, inorganics, and single-element varieties representing a large group of electrical conductors, insulators, and semiconductors with impressive mechanical, thermal, and optical properties. Magnetic members were noticeably absent until just a few months ago, when two chromium compounds joined. The two lone magnetic members have now been joined by a third one—manganese thiophosphite, MnPS₃ (ACS Nano 2017, DOI: 10.1021/acsnano.7b05856). Similar to refrigerator magnets, the chromium compounds are ferromagnetic, meaning their magnetic moments, or spins, point in the same direction. MnPS₃ is a 2-D antiferromagnetic material: The up and down orientations of its spins alternate from one atomic site to the next. Gen Long and Ning Wang of Hong Kong University of Science & Technology and coworkers synthesized flakes of the compound as thin as two atomic layers from a mixture of the elemental powders via a high-temperature method. For now, the ultrathin material provides mainly a means to probe antiferromagnetism in 2-D. In the future, these kinds of materials may be used in cloaking applications that make magnetic data-storage devices and their data invisible.