Nanocap arrays of granular CoCrPt:SiO₂films on silica particles: tailoring of the magnetic properties by Co⁺irradiation

Abstract

An approach for tailoring the magnetic properties by ion irradiation of granular perpendicular CoCrPt:SiO(2) films grown on silica particles with sizes down to 10 nm was investigated. The as-prepared samples reveal an intriguing scaling dependence of the coercive field and remnant magnetization: both parameters are found to decrease with decreasing particle size. However, Co(+) irradiation at a low fluence of 0.5 x 10(14) cm(-2) already results in an opposite scaling behavior. It is assumed that this modification is due to the enhancement of the intergranular magnetic exchange coupling of the granular CoCrPt:SiO(2) film initiated by Co(+) irradiation resulting in a modified reversal behavior. Further increase of the irradiation fluence beyond 1.6 x 10(14) ions cm(-2) leads to a degradation of the magnetic layer properties, lowering the remnant magnetization and the coercive field in the easy-axis direction. Moreover, the local magnetic properties of the samples were analyzed by magnetic force microscopy revealing magnetic multi-domain cap structures.

Crystallization Mechanisms in Convective Particle Assembly

“…Surface roughness affects the interaction with biological systems like cells , and arthropods and the contact angles on superhodrophobic and self-cleaning surfaces . Curvature is an important parameter for magnetic high density data storage or microlens arrays. , Periodic surfaces modulate sound and light, for example, in planar waveguides, diffraction gratings, coatings with bandgaps for certain frequencies, and antireflective coatings . Metal particle layers provide plasmonic wave guides .…”

Magnetic Films on Nanoparticle Arrays

“…Therefore the implementation of CoCrPt as a recording layer also for BPM was proposed [15,63]. In this study, self-assembled arrays of SiO 2 particles of various sizes were utilized to fabricate patterned media based on granular CoCrPt-SiO 2 films [64].…”

“…Recently, we demonstrated the possibility to tune the magnetic properties of CoCrPt-SiO 2 films grown on selfassembled arrays of SiO 2 spherical particles using irradiation with magnetic Co + ions at fluences up to 4.5x10 14 cm -2 [63]. By using magnetic ions, we can directly influence the intergranular exchange by introducing Co atoms into the grain boundaries, which allows us to tailor the magnetic exchange coupling between CoCrPt grains in a controlled manner [65].…”

Magnetic properties of granular CoCrPt:SiO2thin films deposited on GaSb nanocones

“…As an alternative to the conventional lithographic methods, bottom-up approaches employing pre-structured templates prepared by self-organizing processes provide cost-0957-4484/14/085703+06$33.00 and time-efficient nanostructuring on large areas [1,[7][8][9][10][11][12][13]. For example, nanoscale silica spheres can be assembled and covered by ferromagnetic films to form arrays of magnetic nanostructures [14][15][16]. Furthermore, the strain-induced growth of Si 1−x Ge x films on Si(001) leads to self-assembled patterns of nanopyramids, whose facets can be magnetically covered by shadow deposition [7,17,18].…”

“…the deposition pressure, or the buffer layer [33]. It has recently been demonstrated that the magnetic coupling can be tuned by ion irradiation with either non-magnetic or magnetic ions as well, resulting in a pronounced change of the coercivity and remanence [15,34,35].…”