Proved the theory of magnetic memory in two-dimensional materials—now we expect an increase in HDD capacity.

New experimental frontier: a complete cycle of exotic magnetic phases discovered in atomically thin material

Physicists from the University of Texas at Austin have for the first time recorded a fully sequential evolution of two unique magnetic states that previously existed only as separate phases. The experiment enabled the formation of stable “magnetic islands” only a few nanometers in size—a step toward future ultra‑dense data storage devices.

What was discovered?
1. Berezinskii–Kosterlitz–Thouless–Taulese (BKT) phase

When cooled to temperatures between –150 °C and –130 °C, the atomically thin two‑dimensional material enters a BKT state. In this state magnetic moments form pairs of interlinked vortices rotating in opposite directions. Each vortex is confined to a size of only a few nanometers.

2. Six‑state “clock” phase

With further cooling the material transitions into a second phase—a six‑state ordered (six‑state clock) phase. Magnetic moments adopt one of six possible orientations resembling the hands of a clock face. These states are stable and long‑lived, making them potentially suitable for information storage.

These two phases—precursors to each other—had previously been observed separately, but no one had reproduced the full cycle.

Material and methods
The experiment was performed on a crystal of nickel phosphide trisulfide (NiPS₃). The results were confirmed both theoretically and experimentally using nonlinear optical micro‑polarimetry.

Scientific significance
- They confirm fundamental models of two‑dimensional magnetism and topological physics.

- The contribution of Soviet scientist Vadim Berezinskii, the founder of the BKT transition, is validated by experimental data. For developing this theory the 2016 Nobel Prize was awarded to Kostelitz and Taulese.

- Demonstrating stable nanoscale magnetic vortices in a purely two‑dimensional system opens new possibilities for controlling magnetism at the atomic level.

Prospects
Scientists plan to search for materials where these exotic phases are stabilized at higher temperatures—closer to room temperature. This could lead to the creation of ultra‑compact magnetic nanodevices, breakthroughs in spintronics, and new data storage technologies.