Electrically controlled exchange bias for spintronic applications

Abstract

Exchange coupling between a magnetoelectric (111)-oriented Cr2O3 single crystal and a CoPt multilayer with perpendicular anisotropy exhibits an exchange bias field proportional to the applied axial electric field. Extrapolation from bulk to thin film magnetoelectric pinning system suggests promising spintronic applications due to coupling between the electric field-controlled magnetization and the magnetization of a neighbor ferromagnetic layer. Pure voltage control of magnetic configurations of tunneling magnetoresistance spin valves is an attractive alternative to current-induced magnetization switching.

Phase transitions in multiferroic BiFeO3crystals, thin-layers, and ceramics: enduring potential for a single phase, room-temperature magnetoelectric ‘holy grail’

“…Figure 7 also illustrates the spin cycloid transformation under dually-applied electric and magnetic fields: the period of the cycloid decreases with increasing electric field; and at the field region between dashed and solid lines, the cycloid is domain-like and described by a soliton (14a) with The anharmonic character of the cycloid in high magnetic fields becomes apparent in the nonlinear behaviour of the magnetization curve (see Fig.5a) for 150<H<200kOe [4]. This observed experimental dependence (17) can be understood in terms of the sum of spontaneous magnetization M spont averaged over the cycloid's period, and the magnetization M H induced by external field dependence on external field H:…”

“…These findings coupled with those in ME two-phase (nano and macro) composites of piezoelectric and magnetostrictive materials have served as triggers for a "magnetoelectric renaissance": the revival of hope to find a room temperature magnetoelectric material with significant coupling of polar and magnetic subsystems [14][15][16]. As a consequence, multiferroics are now being considered as promising materials for spintronics [17,18], magnetic memory systems, sensors, and tunable microwave devices [19]: offering the potential to revolutionize electromagnetic material's applications. Part I. BiFeO 3 single crystals: unrealized potential.…”

Combining half-metals and multiferroics into epitaxial heterostructures for spintronics

“…Several promising types of devices can be imagined from this combination, as discussed, for instance, by Binek et al 13,14 In particular, one can think of using very thin layers of BiFeO 3 as multiferroic tunnel barriers. If ferroelectric, these layers should have the same functionalities as those of recently developed 15 and modeled 16,17 ferroelectric tunnel barriers, combined with a magnetic ordering and a possible magnetoelectric coupling.…”

Adsorbate/absorbate interactions with organic ferroelectric polymers

“…The source to drain bias is 0.2 V, and hysteresis is evident. Arrows indicate the direction of the gate voltage as it is swept from +4 to −4 V. interfaces with select organometallic compounds, it may be possible to design magneto-electric devices [101,102] with larger induction constants (α ij ) as both molecular orientation and the concomitant magnetic coupling may be significantly altered. In the planar geometry or not, it seems clear that the metal phthalocyanines can be used to make rectifying molecular heterojunctions with PVDF, as in [28,29], and illustrated in Figure 12.…”