Magnetic properties dependence of mesoscopic scale thick films on thickness and surface roughness characteristics: Case of nickel samples in Ni/Pt system

Abstract

Thickness (d) and surface roughness (σ) of material thin films are inseparable characteristics engendered by the same deposition process. Both are crucial parameters for magnetic properties (p) of real mesoscopic scale thick ferromagnetic films. When condition (d/σ) < 102 is validated, sorting out samples of a series is possible only by means of τ = (d/σ) geometrical ratio which enables their coherent comparison. Their magnetic properties (p) are thereby expressed in a single function form p = f(τ). Application of that approach to a series of nanostructured Ni electrodeposits reveals that these samples are consistent with the ratio range 1.23 ≤ τ ≤ 82.00 concurring with the reported description. Their coercivity (Hc) and magnetic domain size (w) behave in agreement with their respective predicted general curve profile when d is substituted by τ, which depicts quite well the similar role of both parameters. The study of these properties evolution using the normalization model indicates a discontinuity in the magnetism of the investigated samples. Bloch magnetic domains (MD)B are associated with mixed domain walls (DWN + DWB) below a critical position (τ0−1) ≈ 0.35, while Néel domain walls (DWN) coexist with mixed magnetic domains (MDB + MDN) beyond that position.