Dipole-induced exchange bias

Abstract

The discovery of dipole-induced exchange bias (EB), switching from negative to positive sign, is reported in systems where the antiferromagnet and the ferromagnet are separated by a paramagnetic spacer (AFM-PM-FM). The magnitude and sign of the EB is determined by the cooling field strength and the PM thickness. The same cooling field yields negative EB for thin spacers, and positive EB for thicker ones. The EB decay profile as a function of the spacer thickness, and the change of sign, are attributed to long-ranged dipole coupling. Our model, which accounts quantitatively for the experimental results, ignores the short range interfacial exchange interactions of the usual EB theories. Instead, it retains solely the long range dipole field that allows for the coupling of the FM and AFM across the PM spacer. The experiments allow for novel switching capabilities of long range EB systems, while the theory allows description of the structures where the FM and AFM are not in atomic contact. The results provide a new approach to design novel interacting heterostructures.

Magnetization Reversal Mechanism in Exchange-Biased Spring-like Thin-Film Composite

“…However, these works focused on AFM/FM bilayer, 27 spin glass/FM interface, 28 or a system where AFM and FM layers are separated by a paramagnetic material. 29 This paper develops this field of research further by combining two magnetic effects in one study—exchange bias and magnetic exchange spring—to find how they affect the reversal process. Such type of FM/AFM/FM composite that we study here is similar to the hard–soft exchange spring materials which can be applied in high-density magnetic recording devices.…”

“…The issue of the cooling field impact on the magnitude and sign of the exchange bias field has been recently raised in a few research papers. However, these works focused on AFM/FM bilayer, spin glass/FM interface, or a system where AFM and FM layers are separated by a paramagnetic material . This paper develops this field of research further by combining two magnetic effects in one studyexchange bias and magnetic exchange springto find how they affect the reversal process.…”

Cooling-field dependence of dipole-induced loop bias

“…) type] interactions [21][22][23][24] may be a source of generating exchange-bias-like phenomena as well, yet based on distinct hidden mechanisms.…”

Tailoring exchange bias in ferro/antiferromagnetic FePt3 bilayers created by He+ beams

“…Exchange bias (EB) has been widely researched for its fundamental scientific importance and for the numerous applications which it serves, including spin-orbit torque devices and spin-electronics implemented in magnetic sensors and non-volatile magnetic random-access memories [1][2][3][4][5]. The EB effect arises exclusively at the interface between ferromagnetic (FM) and antiferromagnetic (AF) layers, after cooling through the Néel temperature of the AF component in an external magnetic field [6,7].…”