Structure and Tunneling Magnetodielectric Effects of Cobalt–(Barium Fluoride) Lateral Nanogranular Films

Controlling the conductance of miniaturized electrical components via spin-dependent tunneling is a challenging step for nano-scale implementation. In this study, we demonstrate the fabrication of lateral nanogranular films with oblate magnetic metal nanoparticles and achieve variable out-of-plane intergranular gap. Changes in insulating layer thickness from 0.4 to 2.1 nm resulted in a marked increase of 10,000-fold for both in-plane and out-of-plane electrical resistivities. A 4% enhancement in permittivity, namely the magnetodielectric effect, was obtained under an in-plane magnetic field of 10 kOe. The frequency at which the maximum magnetodielectric effect is found shifts from 15 kHz to 880 kHz depending on the out-of-plane resistivity. We demonstrated frequency control of the magnetodielectric effect via electrical resistivity by structural modulation of the lateral nanogranular system.