Bi-modified samarium cuprate (Bi_xSm_2−xCuO₄ (0 ≤ x ≤ 0.1)) thermosensitive ceramics with low sintering temperature

The negative temperature coefficient (NTC) thermosensitive ceramics with low sintering temperature are of great significance in the research and application of low-temperature co-firing sensitive components. In this work, bismuth-modified samarium cuprate (Bi_xSm_2-xCuO₄, denoted as xBSCO, x ≤ 0.1) thermistors were prepared by a solid-state reaction method. All ceramics were sintered below 950 °C and show typical NTC effect. The phase component, microstructure, electrical properties of prepared ceramics were investigated. The substitution of Bi-ions reduces the room temperature resistivity (ρ₂₅) of the ceramics. For various contents of Bi-ions, ρ₂₅ of xBSCO ranges from 76 Ω cm to 1297 Ω cm, and all the ceramics have high temperature sensitivity with NTC material constants (B values) between 2237 and 5150 K. The temperature coefficient of resistance at 25 °C (TCR₂₅) of xBSCO is in the range − 5.48% K⁻¹ to − 2.30% K⁻¹. The effect of Bi doping on the structure and property of Sm₂CuO₄ ceramics is discussed basing on the perspective of band structure.