Enhancement of low-field magneto-dielectric response in two-dimensional Co/AlF granular films

Abstract

We report enhanced low-field magneto-dielectric (MD) response in two-dimensional (2D) Co/Al fluoride (AlF) granular films, which comprise 2D crystalline Co granules laminated by AlF amorphous layers. We observed an increase in MD sensitivity under a low magnetic field as the Co layer thickness increased. A small magnetic field (H = 1000 Oe) resulted in a large MD ratio, up to Δε′/ε′ = 0.8% in Co (3 nm)/AlF (5 nm) films. The low-field enhancement was determined to be caused by increasing the granule size and pair density and by the balance between the superparamagnetic and ferromagnetic components in the magnetic granular layers. The 2D granular structure opens another avenue for tailoring magneto-electric properties in high-performance MD devices at room temperature.

Tunnel-Type Magneto-Dielectric Effect and Its Annealing Study in Co–SiO₂ Granular Films

“…12) To enhance the TMD response, many efforts have been devoted by means of improvement in either films structure or experimental design. 13,14) Structurally, by artificially constructing a twodimensional (2D) Co/AlF granular structure, the balanced control of ferromagnetism and super-paramagnetism has been achieved, which is of key importance in producing the lowfield TMD enhancement. 13) Experimentally, we addressed this issues by designing a novel co-separate sputtering method, which is pivotal to deposit the granular structure with clear granule-ceramic boundary to achieve improved TMD effect.…”

“…13,14) Structurally, by artificially constructing a twodimensional (2D) Co/AlF granular structure, the balanced control of ferromagnetism and super-paramagnetism has been achieved, which is of key importance in producing the lowfield TMD enhancement. 13) Experimentally, we addressed this issues by designing a novel co-separate sputtering method, which is pivotal to deposit the granular structure with clear granule-ceramic boundary to achieve improved TMD effect. 14) Whereas these film preparations have so far been limited in metal-fluoride material systems and choices of the fluorides, e.g.…”

Probing the dielectric, piezoelectric and magnetic behavior of CoFe2O4/BNT-BT0.08 composite thin film fabricated by sol-gel and spin-coating methods

“…These composites have applications in electronic devices with novel distinct functionalities 6–8 . Oxide heterostructure thin films with electric and magnetic properties were prepared by various techniques, such as: sol-gel 9 , pulsed laser deposition 10 , rf sputtering 11 , tape-casting method 12 , etc. There are several reports on composites with electrical, ferroelectric and ferromagnetic behaviors, for example: ferroelectric-ferromagnetic composites (BiFeO 3 -CoFe 2 O 4 13 , nickel ferrite-PZT and manganite-PZT 8 , CoFe 2 O 4 -BaTiO 3 14 ) and ferromagnetic-piezoelectric oxide heterostructures (La 0.7 Sr 0.3 MnO 3 -PbZr 0.2 Ti 0.8 O 3 15 , CoFe 2 O 4 –PZT 10 ).…”

Magnetic properties and thermal stability of Co/HfN multilayer films for high-frequency application

“…[1][2][3] The granular films with nanometer-sized ferromagnetic granules dispersed in an insulating matrix display a variety of multifunctional properties, e.g., magnetoresistance 4 and magnetoelectric 5 and soft ferromagnetic effect. 6 Theoretically, the magnetic softness achieved by reduced magnetocrystalline anisotropy can be explained by the random anisotropy model.…”