Enhanced magnetoresistance properties of K-site deficient LaK□MnO manganites synthesized 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 LaK□MnO (LKMO) materials has been investigated. The compounds were synthesized 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 LKMO 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 LKMO 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 LKMO ceramics are promising candidates for application in magnetic sensors.