Magnetocapacitance Properties of Multilayered CoFe₂O₄/BaTiO₃/CoFe₂O₄Thin Film by Pulsed Laser Deposition

Abstract

CoFe 2 O 4 (CFO)/BaTiO 3 (BTO)/CoFe 2 O 4 (CFO) multilayered thin films were deposited on Pt/TiO 2 /SiO 2 /Si substrates by the pulsed laser deposition (PLD) system with KrF excimer laser (λ = 248 nm). BTO, CFO, BTO/ CFO and CFO/BTO/CFO structured thin films were prepared and their crystal structures and microstructures, as well as their magnetic and magneto-electrical properties, were studied. The C-V characteristics of these multilayered thin films with different capacitor structures were obtained to confirm the change in their capacitances under a magnetic field. Finally, the capacitance of the CFO/BTO/CFO thin film as a function of bias voltage under an in-plane magnetic field of 1,000 Oe increased to 951.04 pF at 1 MHz, from 831.90 pF measured under no magnetic field, indicating 14.3% increase in magnetocapacitance.

Modulation of physical properties of oxide thin films by multiple fields

“…This phenomenon has been studied in both single phase materials [47,[243][244][245][246][247] and composite systems. [248][249][250][251] For example, the magnetocapacitance effect has been found in perovskite heterostructures such as LCMO/BTO [248] and LCMO/Ba 1−x Sr x TiO 3 [252] superlattices, manifesting an effective ME coupling in these structures. Colossal magnetocapacitance has been reported in electronic phase-separated man-ganite thin films, and the competition of microscopic ferromagnetic metallic and charge ordered insulating clusters is believed to play a major role in the exhibited colossal magnetocapacitance effect.…”

Change of the magnetocapacitance ratio in ferromagnetic materials

“…The 14.3% increase in the magnetocapacitance was due to the change in the c 0 /a 0 ratio of the BTO thin film [11,12]. In this study, * E-mail: ibshim@kookmin.ac.kr; Fax: +82-02-910-5170 we use Ni 0.98 Co 0.02 Fe 2 O 4 (NCFO) and BTO as the FM and the FE materials, respectively, and compare the results from this study to those from the previous study.…”