| AVS 66th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Thursday Sessions |
| Session MI-ThP |
| Session: | Magnetic Interfaces and Nanostructures Poster Session |
| Presenter: | Sneha Upadhyay, Ohio University |
| Authors: | S.R. Upadhyay, Ohio University K. Meng, The Ohio State University F.Y. Yang, The Ohio State University D. Ingram, Ohio University A.R. Smith, Ohio University |
| Correspondent: | Click to Email |
Exchange bias, a shift in the center for the magnetic hysteresis loop of a magnetic material, has gained a lot of attention due to its application in spintronics. Generally, exchange bias is observed in layered magnetic structure like antiferromagnetic/ferromagnetic bilayers. In this work, the L10 MnGa (Tc= 590K) / θ-MnN (TN= 660K) bilayer on MgO substrate was studied for the investigation of exchange bias motivated by the recent report of giant exchange bias using MnN as the antiferromagnet.[1]
These bilayers were prepared using molecular beam epitaxy, and the growth was monitored by in-situ RHEED. Three samples were grown with MnN thickness of 47 nm while L10 MnGa thicknesses were varied from 15nm, 3nm and 1 nm. During the growth, RHEED images were taken which showed some disorder and roughness on the surfaces especially for thinner ones. In order to observe exchange bias, these samples were field cooled through the Néel temperature and the hysteresis was taken at a specific applied field using SQUID. The measurements showed the presence of a small but finite exchange bias in the case of the 3 nm L10 MnGa/θ-MnN sample in the in-plane direction only, and the amount of loop shift from the origin was estimated to be 300 Oersted. The results were compared with the recent publication for the case of CoFeB/ θ-MnN which showed giant exchange bias (3600 Oersted).
Although the field cooling procedure is important to observe exchange bias, in our previous measurements, we were unable to field cool through the high Néel temperature of MnN. Currently, we are working on a new field cooling capability in our MBE chamber and further plan to study the sample using in-situ spin-polarized scanning tunneling microscopy under an applied magnetic field. We also plan to repeat the SQUID measurements as well with the high-temperature, field-cooled sample.
[1] P. Zilske, D. Graulich, M. Dunz, and M. Meinert, "Giant perpendicular exchange bias with antiferromagnetic MnN," Appl. Phys. Lett. 110, 192402 (2017).