Correlation of structural and electrical properties of gadolinium-substituted cobalt ferrites for data storage applications

Gadolinium-substituted cobalt ferrite (CoFe 2-x Gd x O 4 ) nanoparticles with varying gadolinium concentrations (x = 0.0, 0.1, 0.2) were successfully synthesized via a sol-gel method to investigate their structural and electrical properties. The addition of gadolinium, a rare-earth element, is expected to enhance the material's structural and electrical properties, making it suitable for a wide range of applications, including data storage e.g.: ReRAM (Resistive Random Access Memory). X-ray diffraction (XRD) analysis confirmed the formation of a single-phase (∼100 % based on XRD analysis) spinel structure for all compositions, showing alterations such as a decrease in lattice parameter, volume, and crystallite size due to gadolinium substitution. The frequency-dependent dielectric constant, AC electrical conductivity, dielectric loss, dielectric loss tangent, and impedance were investigated in the frequency range of 100 Hz to 3 MHz. In AC analysis, AC electrical conductivity increases but dielectric constant and dielectric tangent loss decrease. In impedance, the contributions of grains and grain boundaries, as well as their effects within the spinel ferrite structure, are analyzed under ambient temperature conditions (∼25°C) to understand their impact on the material's overall electrical behavior. In DC analysis, DC resistivity and activation energy increase with increases in gadolinium concentration. The I-V measurements indicated the presence of resistive switching behavior with hysteresis loops present in all curves of Gd substituted CoFe nanoparticles. Our study offers a deep understanding of how gadolinium doping enhances the properties of cobalt ferrite, making it more suitable to be used in advanced technology applications like data storage. To the best of our knowledge, this work is the first to establish the direct correlation between Gd 3+ substitution in CoFe 2 O 4 and its resistive switching behavior governed by the space charge limited conduction (SCLC) mechanism, extending its potential toward ReRAM applications beyond conventional structure and dielectric studies. I-V curves for CoFe 2-x Gd x O 4 (x = 0.0–0.2)