Superior La0.67K0.33-xSrxMnO3 films with room-temperature TCR prepared by spin coating method

La 0.67 K 0.33- x Sr x MnO 3 thin films were grown on LaAlO 3 ( 010 ) substrates via sol–gel and spin coating methods. The replacement of K ions with Sr ions affected the e g electron bandwidth and concentration of Mn 3+ /Mn 4+ pairs as well as effectively modulated the magnetic/orbital order and lattice structure. Consequently, the ferromagnetic metal to paramagnetic insulation transition was affected, which further optimized the resistivity, temperature coefficient of resistivity ( TCR ), peak TCR temperature ( T K ), and peak resistivity temperature ( T P ). At temperatures below 230 K, temperature-independent scattering and electron-electron scattering were practically not observed in the films. Overall, electrical properties of films improved with an increase in the Sr doping content. The superior La 0.67 K 0.27 Sr 0.06 MnO 3 film exhibited a maximum TCR of 11.88% K −1 (298.3 K), which is approximately 31% higher than that of bulk ceramic with the same composition . The as-developed films exhibit significant potential for application in uncooled infrared bolometers .