Sub-micron magnetic patterns and local variations of adhesion force induced in non-ferromagnetic amorphous steel by femtosecond pulsed laser irradiation

• Published in: Applied surface science 2016-05, Vol.371, p.399-406
• Main Authors: Zhang, Huiyan, Feng, Yuping, Nieto, Daniel, García-Lecina, Eva, Mcdaniel, Clare, Díaz-Marcos, Jordi, Flores-Arias, María Teresa, Gerard M., O’connor, Baró, Maria Dolors, Pellicer, Eva, Sort, Jordi
• Format: Article
• Language: English
• Subjects: Adhesion; Adhesion force; Amorphous steel; Femtosecond pulsed laser irradiation; Femtosecond pulsed lasers; Ferromagnetism; Irradiation; Magnetic patterning; Nanostructure; Ripples; Structural steels; Surface ripples; Wettability
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.03.011

[Display omitted] •Formation of ripples after femtosecond pulsed laser irradiation (FSPLI) of metallic glass was studied.•Magnetic patterning at the surface of non-ferromagnetic amorphous steel was induced by FSPLI.•The origin of the generated ferromagnetism is the laser-induced devitrification. Periodic ripple and nanoripple patterns are formed at the surface of amorphous steel after femtosecond pulsed laser irradiation (FSPLI). Formation of such ripples is accompanied with the emergence of a surface ferromagnetic behavior which is not initially present in the non-irradiated amorphous steel. The occurrence of ferromagnetic properties is associated with the laser-induced devitrification of the glassy structure to form ferromagnetic (α-Fe and Fe3C) and ferrimagnetic [(Fe,Mn)3O4 and Fe2CrO4] phases located in the ripples. The generation of magnetic structures by FSPLI turns out to be one of the fastest ways to induce magnetic patterning without the need of any shadow mask. Furthermore, local variations of the adhesion force, wettability and nanomechanical properties are also observed and compared to those of the as-cast amorphous alloy. These effects are of interest for applications (e.g., biological, magnetic recording, etc.) where both ferromagnetism and tribological/adhesion properties act synergistically to optimize material performance.