| AVS 58th Annual International Symposium and Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Thursday Sessions |
| Session MI-ThM |
| Session: | Emerging Magnetic Characterization and Results |
| Presenter: | Kangkang Wang, Ohio University |
| Authors: | K. Wang, Ohio University A.V. Chinchore, Ohio University W. Lin, Ohio University A.R. Smith, Ohio University |
| Correspondent: | Click to Email |
Antiferromagnets play a critical role in spintronic applications such as pinning layers in magnetic memories. The development of spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM/STS) has shown its unprecedented power in resolving the local spin and domain structures of antiferromagnetic surfaces down to atomic level.1-6 While most efforts have been made on imaging metal surfaces at cryogenic temperatures, only a few have been devoted to the study of room-temperature magnetic systems.4-6 Here we apply SP-STM/STS to study the local spin and magnetic properties of a technologically driven material system which exhibits layer-wise antiferromagnetism with a very high Néel temperature (>900 K)7. Mn3N2(001) thin films have been grown on MgO(001) substrates using ultra high vacuum plasma-assisted molecular beam epitaxy and transferred in situ to a home-built room-temperature SP-STM8 for magnetic imaging. Results have shown that the surface exhibits a topological spin pyramid structure with alternating single Mn- and double MnN- layers, where the magnetism is strongly correlated with the surface topography. Using SP-STM with dI/dV mapping, different layers can be clearly distinguished due to their different conductance. These differences in the conductance are a result of not only the different chemical environments, but also the spin ordering and the broken symmetry at the surface. We will show that it is possible to separate the contributions from both the electronic and the magnetic structure by applying a small magnetic field. The field rotates the tip magnetization axis causing concomitant change in the magnetic sensitivity while keeping the electronic structure unchanged. The demonstrated ability of direct imaging at room-temperature of the surface antiferromagnetic terraces allows further (ongoing) studies on the interplay between structural defects such as anti-phase domain boundaries and the formation of intriguing antiferromagnetic domains. We gratefully acknowledge support from the Department of Energy and the National Science Foundation.
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8. K. Wang et al, Rev. Sci. Instrum. 82, 053703 (2011).