Effect of Nanoscale Defect Structure on Magnetic Properties of Tb–Co Films with Perpendicular Magnetic Anisotropy

Abstract

Magnetization reversal is studied for Ta/Tb₂₉Co₇₁/Ta thin films with different types of nanostructure. The films are deposited onto structuring substrates of anodized aluminum with unpolished surfaces, polished surfaces, and barrier layers. Nanoholes are found to triple the coercivity, due likely to the pinning of domain walls. Continuous and antidot films reveal the strong effect nanoconvexities have on the slope of the hysteresis loops. Such surface features could be one of the main reasons for the attenuation of perpendicular anisotropy in films deposited onto porous substrates.