Magnetic anisotropy in the exchange-biased laser-patterned thin Co/CoO films

Abstract

Materials exhibiting an exchange bias effect are a class of magnetic systems that have a wide range of possible technological applications e.g. in sensors, read heads, and spintronic devices. In this study, we demonstrate the effect of laser interference patterning on the magnetic properties of Pd/CoO/Co/Pd multilayers. Laser patterning creates arrays of well-ordered stripes, rectangles, and squares on the substrate surface. We found that the laser treatment caused magnetic softening of the structure edges while the centers of the objects remained unchanged and exhibited the exchange bias effect. In this study we focused on the shape and configurational magnetic anisotropies induced by patterning and showed that the magnetic properties varied depending on the angle at which the external magnetic field was applied with respect to the pattern geometry.

Anisotropy in magnetic materials for sensors and actuators in soft robotic systems

“…Perzanowski et al studied the relationship between patterns of magnetic thin-film layers and exchange bias. 132 The hysteresis curve of a striped pattern exhibited a bias of 0.8 kOe away from the center (Fig. 9e), which was higher than that of a flat film.…”

“…Layered structures of 2D FM and AFM thin films hold a prominent position in the field of spintronic applications based on exchange bias. These layered 2D magnetic thin films provide relatively large-area controllability and easy-tuning of their geometry (dot, 129,130 ring, 131 stripe, 132,133 and wire 134 ), which can be fabricated using various patterning processes including photolithography, 53 and electron beam lithography 130,131 for micro/nano-fabrication. Moreover, the sequential deposition of FM/AFM layers enables the adjustment of surface roughness, [135][136][137] layer thickness, [138][139][140][141][142] and interfacial lattice by regulating the crystallinity of each magnetic thin-film layer.…”

“…Reproduced with permission. 132 Copyright 2022, IOP Publishing. (f ) SEM images of Ta (5 nm)/NiFe (20 nm)/IrMn (7 nm)/Ta (5 nm) rings with inner diameters of (i) 0.35 and (ii) 1.10, and an outer diameter of 2.0 μm.…”

“…151 As mentioned previously, conventional deposition and patterning processes are highly suitable for manufacturing layered structures in 2D magnetic thin films. This compatibility of fabrication allows for the customizing of shape and size, ranging from the submicron 129,130,132 to the nanometer scale, 152 in the development of high-performance spintronic devices including spin valve magnetic field sensors, 54,153 magnetic storage devices, and non-volatile magnetic random access memories. 55,154 Optimization of the geometry and size of patterned magnetic thin-film layers can boost the exchange bias field for spintronics applications.…”

“…The upper and lower loops were measured under horizontal and vertical magnetic fields relative to the length direction of the stripes at 10 K, respectively. Reproduced with permission 132. Copyright 2022, IOP Publishing.…”