Effects of annealing and conformal alumina passivation on anisotropy and hysteresis of magneto-optical properties of cobalt slanted columnar thin films

• Published in: Applied surface science Vol. 421; pp. 320 - 324
• Main Authors: Briley, Chad, Mock, Alyssa, Korlacki, Rafał, Hofmann, Tino, Schubert, Eva, Schubert, Mathias
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2017
• Subjects: Anisotropic magnetic hysteresis; Atomic layer deposition; Heat treatment; Slanted columnar thin films; Vector magneto-optical generalized ellipsometry; Anisotropic magnetic hysteresis; Slanted columnar thin films; Heat treatment; Vector magneto-optical generalized ellipsometry; Atomic layer deposition
• ISSN: 0169-4332; 1873-5584; 1873-5584
• DOI: 10.1016/j.apsusc.2016.12.198

[Display omitted] •Reveal magneto-optical response of cobalt slanted columnar thin films prior to and after heat treatment.•Study passivation effects of conformal alumina coating on magneto-optical properties.•Demonstrate loss of measurable magneto-optical response from cobalt oxide slanted columnar thin films from heat treatment. We present magneto-optical dielectric tensor data of cobalt and cobalt oxide slanted columnar thin films obtained by vector magneto-optical generalized ellipsometry. Room-temperature hysteresis magnetization measurements were performed in longitudinal and polar Kerr geometries on samples prior to and after a heat treatment process with and without a conformal Al2O3 passivation coating. The samples have been characterized by generalized ellipsometry, scanning electron microscopy, and Raman spectroscopy in conjuncture with density functional theory. We observe strongly anisotropic hysteresis behaviors, which depend on the nanocolumn and magnetizing field orientations. We find that deposited cobalt films that have been exposed to heat treatment and subsequent atmospheric oxidation into Co3O4, when not conformally passivated, reveal no measurable magneto-optical properties while cobalt films with passivation coatings retain highly anisotropic magneto-optical properties.