Enhanced magnetoresistance properties of K-site deficient La_0.85K_0.1□_0.05MnO₃ manganites synthesized via sol-gel, wet-mixing, and solid-state reaction methods

The effect of synthesis methods on the structural, magnetic, electrical transport, and magnetoresistance (MR) properties of K-deficient La_0.85K_0.1□_0.05MnO₃ (LK_dMO) materials has been investigated. The compounds were synthesized via sol-gel (SG), wet-mixing (WM), and solid-state (SS) reaction. The resulting ceramics were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and four point probe (FPP) techniques to evaluate their crystal structure, morphologies, elemental composition, electrical transport properties, and magnetoresistance (MR) behavior. This study reveals that the electrical- and magneto-transport properties of LK_dMO ceramics are strongly influenced by their synthesis method. Among the samples, the WM method yielded ceramics with smaller grain sizes and more dispersed grain boundaries, leading to reduced resistivity. The MR values for LK_dMO ceramics synthesized through SG, WM, and SS reached 17.05% at 287.74 K, 54.68% at 271.50 K, and 47.09% at 270.25 K, respectively. The WM-synthesized sample exhibited superior crystal quality and enhanced magnetic and electrical properties. These results indicate that LK_dMO ceramics are promising candidates for application in magnetic sensors.