A joint team of scientists from China and Korea for the first time observed the magnetic skyrmions in few layers oxide thin films, which had only been measured by Hall Effect.

In addition, the team realized control of magnetic skyrmions in that ultrathin oxide hetero structures.

This study was conducted by Prof. LU Qingyou''s team from High Magnetic Field Laboratory, Chinese Academy of Sciences (CHMFL) and Prof. Noh’s group from Seoul National University. The study was published in Nature Materials.

According to the team, they made the study through the low-temperature and high-magnetic-field magnetic force microscopy (or MFM) developed themselves.

The magnetic skyrmion is a whirled spin structure that is topologically protected and could be down to nanoscale. Its particle-like dynamics and high mobility under driving current make it a popular candidate for the new generation information storage, which places it into the spotlight.

However, skyrmions have rarely been observed, especially in oxide thin films, due to its small size (typically in nanometer scale) and weak magnetism.

Prof. Noh’s group has explored possible magnetic skyrmions in the BTO/SRO thin films via Hall measurements. A direct microscale imaging was needed to further confirm the existence of skyrmions. Therefore, MFM microscopy came to mind.

In this study, Prof. LU's team performed MFM on the sample, and obtained a series of possible skyrmions structures as various magnetic fields ranging from 5 T to -5 T.

To eliminate the unwilling background contrasts originating from the terrace edges, they performed pixel-by-pixel subtraction to every pair of MFM images with small magnetic field difference.

The resulting images showed clear individual skyrmions as well as skyrmion clusters or magnetic bubbles.

Through the MFM measurements, some fundamental information about skyrmions such as size, density, and dynamical behavior were also clearly revealed.