Systematic study of magnetotransport properties and enhanced low-field magnetoresistance in thin films of La_0.67Sr_0.33MnO₃ + Mg(O) Available to Purchase

La, Sr, Mn, and Mg precursors were mixed in stoichiometric ratio 0.67/0.33/1/x with solvent and were spin-coated onto (001) LaAlO₃ substrates. X-ray diffraction and elemental mapping of these films indicate that for small addition of Mg precursor, Mg²⁺ acts as a dopant in La_0.67Sr_0.33MnO₃ phase and for higher concentrations, MgO phase separates out. Curie temperature and metal-insulator transition temperature systematically decrease with increasing molar concentration of Mg(O). Low-field magnetoresistance of films significantly enhanced by Mg addition and for the highest amount of Mg at 10 K, values were −35.5% and −83.2% with 0.5 T and 3 T applied fields, respectively.