Science Daily January 19, 2023
Tunnelling magnetoresistance (TMR) is considered to be proportional to spin polarization at the interface and has been studied primarily in ferromagnets. An international team of researchers (Japan, Canada) observed TMR in an all-antiferromagnetic tunnel junction consisting of Mn3Sn/MgO/Mn3Sn. They made measurements using a Fe/MgO/Mn3Sn MTJ and showed that the sign and direction of anisotropic longitudinal spin-polarized current in the antiferromagnet can be controlled by octupole direction. They measured a TMR ratio of around 2% at room temperature, which arises between the parallel and antiparallel configurations of the cluster magnetic octupoles in the chiral antiferromagnetic state. The TMR ratio (about 2%) of the all-antiferromagnetic MTJ is much larger than that estimated using the observed spin polarization. Theoretically, they found that the chiral antiferromagnetic MTJ may produce a substantially large TMR ratio as a result of the time-reversal, symmetry-breaking polarization characteristic of cluster magnetic octupoles. Their work lays the foundation for the development of ultrafast and efficient spintronic devices using antiferromagnets…read more. Open Access TECHNICAL ARTICLEÂ
Antiferromagnetic tunnel junction with cluster magnetic octupoles. Credit: Nature volume 613, pages490–495 (2023)Â