Unravelling the tunable exchange bias-like effect in magnetostatically-coupled two dimensional hybrid (hard/soft) composites

Abstract

Hybrid 2D hard-soft composites have been fabricated by combining soft (Co73Si27) and hard (NdCo5) magnetic materials with in-plane and out-of-plane magnetic anisotropies, respectively. They have been microstructured in a square lattice of CoSi anti-dots with NdCo dots within the holes. The magnetic properties of the dots allow us to introduce a magnetostatic stray field that can be controlled in direction and sense by their last saturating magnetic field. The magnetostatic interactions between dot and anti-dot layers induce a completely tunable exchange bias-like shift in the system's hysteresis loops. Two different regimes for this shift are present depending on the lattice parameter of the microstructures. For large parameters, dipolar magnetostatic decay is observed, while for the smaller one, the interaction between the adjacent anti-dot's characteristic closure domain structures enhances the exchange bias-like effect as clarified by micromagnetic simulations.

All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice

“…Tunable exchange bias-like effects in magnetostatically-coupled 2D hybrid composites are studied earlier by A. Hierro-Rodriguez et al [37]. Also, Yu et al…”

“…In addition to the better tunability of magnonic band structure, a larger propagation velocity of SWs has been demonstrated due to the presence of direct exchange coupling between the two materials in a filled antidot lattice (ADL) [34]. Tunable exchange bias-like effects in magnetostatically-coupled 2D hybrid composites are studied earlier by Hierro-Rodriguez et al [35]. Also, Yu et al demonstrated that a grating coupler of periodically nano-structured magnets provokes multidirectional emission of short-wavelength SWs with enhanced amplitude compared with a bare microwave antenna [36].…”

Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

“…The fabrication of the magnetic circuit, composed of a cobalt bridge overcrossing a cobalt microwire, has been made by electron beam lithography using a Raith Elphy Plus e-beam lithography system installed in a LEO EVO 60 Scanning Electron Microscope [8]. Cobalt structures have been grown with magnetron DC sputtering from pure Co targets at normal incidence [8].…”

“…Cobalt structures have been grown with magnetron DC sputtering from pure Co targets at normal incidence [8].…”

Non-Exchange Bias in Binary Nanoparticle Systems

“…Dipolar interactions have, for example, recently been shown to play a critical role in certain multilayer systems, namely, in the long-range "exchange bias" in ferromagnetic-antiferromagnetic heterostructures separated by non-magnetic layers 19,20 . In addition, dipolar-induced exchange-biaslike effects have been extensively studied in pseudo-spin valve like structures, i.e., hard and soft ferromagnetic layers separated by a non-magnetic layer 21,22 . Similar effects have also been observed in hard/soft nanostructured systems 23 .…”