Abstract

In this work, polycrystalline La0.845Sr0.155MnO3:Ag0.4 (LSMO:Ag) ceramics were synthesized via a combined sol–gel and solid-state method with various sintering times. The structure and unique electrical and magnetic properties of the synthesized ceramics were examined in detail. The optimized sintering temperature was determined to be 1723 K. At this temperature, by changing the sintering time from 5 to 14 h, the temperature coefficient of resistivity (TCR) and the magnetic resistance (MR) of the LSMO:Ag samples could be quickly improved. The results show that La3+ and Sr2+ ions were gradually substituted by Ag+ ions with increasing sintering time. The substitution resulted in changes to the Mn3+–O–Mn4+ pairs and a distortion of the MnO6 octahedron, which could be attributed to the double exchange (DE) and Jahn–Teller (JT) effects. At a sintering time of t = 10 h, a peak TCR value of 17.82% K−1 was attained and was achieved at room-temperature (Tk, 299.9 K). This work demonstrates an effective approach to obtain high TCR and MR values at room-temperature for uncooled manganite devices by optimizing the sintering time.

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