High-density Néel-type magnetic skyrmion phase stabilized at high temperature

The discovery of a thermally stable, high-density magnetic skyrmion phase is a key prerequisite for realizing practical skyrmionic memory devices. In contrast to the typical low-density Néel-type skyrmions observed in technologically viable multilayer systems, with Lorentz transmission electron microscopy, we report the discovery of a high-density homochiral Néel-type skyrmion phase in magnetic multilayer structures that is stable at high temperatures up to 733 K (≈460 °C). Micromagnetic simulations reveal that a high-density skyrmion phase can be stabilized at high temperature by deliberately tuning the magnetic anisotropy, magnetic field, and temperature. The existence of the high-density skyrmion phase in a magnetic multilayer system raises the possibility of incorporating chiral Néel-type skyrmions in ultrahigh-density spin memory devices. Moreover, the existence of this phase at high temperature shows its thermal stability, demonstrating the potential for skyrmion devices operating in thermally challenging modern electronic chips. Magnetic materials: High-density storage for low-power memory High-density, stable magnetic patterns that could be useful for energy-efficient computer memory have been created by scientists in South Korea. Skyrmions, magnetic patterns that behave somewhat like particles, are a promising technology for a new generation of low-power-consumption computer memory. A key requirement for such an application is a material that can support skyrmions at a high density to maximize the amount of information that can be stored. Hye Jung Chang and Jun Woo Choi from the Korea Institute of Science and Technology in Seoul and their co-workers have created a stack of magnetic thin films and observed so-called Néel skyrmions. Using an electron microscope, the team were able to observe high-density Néel skyrmions that were stable over a wide range of temperatures up to around 460 °C. Combining Lorentz transmission electron microscopy and micromagnetic simulations, we discover a high-density homochiral Néel-type skyrmion phase in a Pt/Co/Ru/Pt/CoFeB/Ru magnetic multilayer structure that is stable at high temperatures up to 733 K. The domain phase in this system can be modulated between a high-density skyrmion phase, an isolated skyrmion phase, or a stripe domain phase by appropriate tuning of external and material parameters. This finding suggests that multilayer Néel-type skyrmions can be utilized in nonvolatile spin-based electronic devices t