Tuning room-temperature TCR of La0.7K0.3−xSrxMnO3 (0.00 ≤ x ≤ 0.3) films by K and Sr co-occupying A-site

A series of La 0.7 K 0.3− x Sr x MnO 3 (0.00 ≤  x  ≤   0.3) films were fabricated on LaAlO 3 substrates using a sol-gel spin-coating technique. The relationship between electrical transport properties and a microstructure was explained via the Jahn–Teller effect, a phenomenological percolation model, and a double-exchange mechanism. The results revealed the strong impact of K and Sr co-occupying A-sites on the formation of Mn 3+ /Mn 4+ pairs, crystal structure, conductivity, surface morphology, and in-plane and out-of-plane strains. The as-fabricated La 0.7 K 0.25 Sr 0.05 MnO 3 films showed a peak temperature coefficient of resistivity of 16.63% K −1 at 298.3 K.