A.C. conductivity, Dielectric and Electric Modulus Studies of LiMn_2O_4 cathode films grown by RF magnetron sputtering

摘要

Spinel LiMn_2O_4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering method. All the grown thin films were post-annealed up to 500 °C, in the presence of oxygen to enrich the crystallinity of the thin film. XRD and Raman results showed the formation of the cubic spinel structured LMO thin film annealed at 500 °C. AFM micrographs of LMO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (s'), and electric modulus (M") for the as-deposited and post-annealed LMO thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.