Detection of uncompensated magnetization at the interface of an epitaxial antiferromagnetic insulator

Authors

Pavel N. Lapa, University of California, San Diego
Min Han Lee, University of California, San Diego
Igor V. Roshchin, Texas A&M University
Kirill Belashchenko, University of Nebraska - LincolnFollow
Ivan K. Schuller, University of California, San Diego

ORCID IDs

Min-Han Lee https://orcid.org/0000-0001-9093-4891

Kirill D. Belashchenko https://orcid.org/0000-0002-8518-1490

Ivan K. Schuller https://orcid.org/0000-0002-9078-7120

Document Type

Article

Date of this Version

11-5-2020

Citation

PHYSICAL REVIEW B 102, 174406 (2020)

DOI: 10.1103/PhysRevB.102.174406

Comments

©2020 American Physical Society. Used by permission.

Abstract

We have probed directly the temperature and magnetic field dependence of pinned uncompensated magnetization at the interface of antiferromagnetic FeF₂ with Cu, using FeF₂-Cu-Co spin valves. Electrons polarized by the Co layer are scattered by the pinned uncompensated moments at the FeF₂-Cu interface giving rise to giant magnetoresistance. We determined the direction and magnitude of the pinned uncompensated magnetization at different magnetic fields and temperatures using the angular dependencies of resistance. The strong FeF₂ anisotropy pins the uncompensated magnetization along the easy axis independent of the cooling field orientation. Most interestingly, magnetic fields as high as 90 kOe cannot break the pinning at the FeF₂-Cu interface. This proves that the pinned interfacial magnetization is strongly coupled to the antiferromagnetic order inside the bulk FeF₂ layer. Studies as a function of FeF₂ crystalline orientation show that uncompensated spins are only detected in a spin valve with (110) crystal orientation, but not in valves containing FeF₂(100) and FeF₂(001). This observation is in agreement with symmetry-related considerations which predict the equilibrium boundary magnetization for the FeF₂(110) layer.