Investigations on electronic structure and transport property modifications of La0.7Ca0.3-xKxMnO3 ceramics

The partial substitution of monovalent alkali metal K⁺ at the divalent Ca²⁺ site in La_0.7Ca_0.3MnO₃ manganites (LCKMO) leads to remarkable structural, electronic, and magnetic modifications. This report combines structural, transport, magneto transport, and X-ray photoelectron spectroscopy (XPS) studies to examine these modifications in LCKMO samples with varying alkali metal content. X-ray diffraction (XRD) confirmed the orthorhombic crystal structure and single-phasic nature, while transport and magnetoresistance studies highlighted the effects of K⁺ substitution on the metal-insulator transition temperature (T_P) and resistivity. X-ray Photoelectron Spectra (XPS) analysis decodes the Mn³⁺/Mn⁴⁺ mixed-valence states, providing insights into the Jahn-Teller (JT) distortions and double-exchange (DE) mechanisms manipulating the observed magnetic behaviour. These findings highlight the carping interplay of structural and electronic modifications in tailoring the functional properties of manganites for potential technological applications.