Non-Linear Hysteresis in La-Doped Ferrites for Advanced Electronics

Lanthanum-doped cobalt ferrite Nanoparticles with composition CoLa x Fe 2−x O 4 , (x=0.00–0.20) were synthesized by a co-precipitation method. X-ray diffraction (XRD) confirm the formation of single-phase spinel structure for all synthesized samples. The result of Lanthanum doping on dielectric, AC electrical, DC electrical and current-voltage (I-V) properties of spinel cobalt ferrite were investigated. Dielectric constant and dielectric loss decrease with increasing frequency whereas ac conductivity increases with increasing frequency. Role of grain and grain boundary on impedance has been explored from Nyquist plots and equivalent electrical circuits were proposed to clarify the impedance spectroscopy results. Activation energies and drift mobility were estimated from the DC electrical resistivity measurements. DC electrical resistivity decreases with increasing temperature. DC resistivity and drift mobility decreases with Lanthanum doping while Activation energy increases. Maximum value of DC resistivity achieved was 9.26 x 10 +8 (Ω-cm) with crystallite size 17 nm. Current-Voltage measurements were carried out within 0→6V→0V→ – 6V→0V voltage range. It is worth mentioning that all doped sample exhibited remarkable and improved nonlinear hysteresis loop-type behavior than pour sample. This endorsed that resistive switching effect exist in studied samples within 0→6V→0V→ – 6V→0V voltage range. Variation in resistance, during resistive switching, is explained by considering space charge limited conduction (SCLC) model and oxygen vacancies migration across the metal-semiconductor interface. Out study suggest that La doped cobalt ferrites may be tested as an active material for possible applications in non-volatile memory devices and neuromorphic applications