On the redistribution of charge in La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 multilayer thin films

Aubrey N Penn,Divine P Kumah,Sanaz Koohfar,James M Lebeau

doi:10.1063/1.5140352

Aubrey N Penn, Divine P Kumah + Show 2 more

Open Access

PDF Available

https://doi.org/10.1063/1.5140352

Copy DOI

Export

Save

Cite

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

The atomic and electronic structures of La0.7Sr0.3MnO3 (LSMO)/La0.7Sr0.3CrO3 (LSCO) multilayer thin films are investigated using aberration corrected scanning transmission electron microscopy (STEM) imaging and spectroscopy. Atomic resolution high angle annular dark-field reveals that LSMO layers have an expanded out-of-plane lattice parameter compared to compressed LSCO layers, contrasting with x-ray diffraction measurements. The expansion is found to result from preferential oxygen vacancy formation in LSMO during STEM sample preparation as determined by electron energy-loss spectroscopy. The La/Sr atom column intensity is also found to oscillate by about 4% between the LSMO and LSCO layers, indicative of La/Sr concentration variation. Using energy-dispersive x-ray spectroscopy in combination with image simulations, we confirm the La/Sr inhomogeneity and elucidate the origin of charge redistribution within the multilayer. These results illuminate the sensitivity of the technique to subtle structural, chemical, and electronic features that can arise to compensate charge imbalances in complex oxide heterostructures.

Highlights

La0.7Sr0.3MnO3 (LSMO) has the highest Curie temperature of the manganites and is a promising candidate for applications in magnetic memory and spintronic devices.1 Adopting the ABO3 perovskite structure, the mixed charge A-site cations, Sr2+ and La3+, cause the B-site Mn to exist in both 3+ and 4+ states within the structure
Magnetism in LSMO is governed by these exchange interactions that are sensitive to the average Mn charge state and the Mn–O–Mn bonding; the properties of LSMO can be tuned by engineering epitaxial strain and/or film composition
The application of ultra-thin LSMO films in devices has been stymied by the presence of a region of reduced magnetic character that arises near the interface, referred to as the magnetic dead layer (MDL)

Summary

Introduction

La0.7Sr0.3MnO3 (LSMO) has the highest Curie temperature of the manganites and is a promising candidate for applications in magnetic memory and spintronic devices.1 Adopting the ABO3 perovskite structure, the mixed charge A-site cations, Sr2+ and La3+, cause the B-site Mn to exist in both 3+ and 4+ states within the structure.

Results

Conclusion