Abstract
The proximity effect is used to engineer interface effects such as magnetoelectric coupling, exchange bias, and emergent interfacial magnetism. However, the presence of a magnetic “dead layer” adversely affects the functionality of a heterostructure. Here, it is shown that by utilizing (111) polar planes, the magnetization of a manganite ultrathin layer can be maintained throughout its thickness. Combining structural characterization, magnetometry measurements, and magnetization depth profiling with polarized neutron reflectometry, it is found that the magnetic dead layer is absent in the (111)-oriented manganite layers, however, it occurs in the films with other orientations. Quantitative analysis of local structural and elemental spatial evolutions using scanning transmission electron microscopy and electron energy loss spectroscopy reveals that atomically sharp interfaces with minimal chemical intermixing in the (111)-oriented superlattices. The polar discontinuity across the (111) interfaces inducing charge redistribution within the SrTiO3 layers is suggested, which promotes ferromagnetism throughout the (111)-oriented ultrathin manganite layers. The approach of eliminating problematic magnetic dead layers by changing the crystallographic orientation suggests a conceptually useful recipe to engineer the intriguing physical properties of oxide interfaces, especially in low dimensionality.
| Original language | English |
|---|---|
| Article number | 1800922 |
| Journal | Advanced Functional Materials |
| Volume | 28 |
| Issue number | 30 |
| DOIs | |
| State | Published - Jul 25 2018 |
Funding
E.-J.G. and M.A.R. contributed equally to this work. We thank Dr. Yaohua Liu for the valuable discussions and Dr. Liusuo Wu for the kind assistant on the magnetometer measurements. This work was supported by the U.S. Department of Energy (DOE), Office of Science (OS), Basic Energy Sciences (BES), Materials Sciences and Engineering Division (sample design, fabrication, and physical property characterizations) at Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC, for the U.S. DOE. The research at ORNL’s SNS was sponsored by the Scientific User Facilities Division, BES, U.S. DOE. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE, OS, User Facility. The authors acknowledge the use of facilities within the Eyring Materials Center at Arizona State University. E.-J.G. and M.A.R. contributed equally to this work. We thank Dr. Yaohua Liu for the valuable discussions and Dr. Liusuo Wu for the kind assistant on the magnetometer measurements. This work was supported by the U.S. Department of Energy (DOE), Office of Science (OS), Basic Energy Sciences (BES), Materials Sciences and Engineering Division (sample design, fabrication, and physical property characterizations) at Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC, for the U.S. DOE. The research at ORNL's SNS was sponsored by the Scientific User Facilities Division, BES, U.S. DOE. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE, OS, User Facility. The authors acknowledge the use of facilities within the Eyring Materials Center at Arizona State University.
Keywords
- charge discontinuity
- interfacial magnetization
- magnetic tunneling junction
- manganite
- polarized neutron reflectometry