When: Friday, March 26, 2021, 4:30 PM - 5:30 PMWhere: Online
Speaker: Junning Li
Abstract: Solid-state cooling methods based on field-driven first-order phase transitions are often limited by significant hysteresis and small temperature span, which increase the input work required to drive the cooling cycle reversibly and reduce the temperature range of operation. In this topic, we have studied two molecular crystals, fullerene C60 and layered hybrid perovskite (C10H21NH3)2MnCl4. We show that giant and colossal reversible caloric effects can be driven using low hydrostatic pressures across their order-disorder first-order phase transition due to a small transition hysteresis and a high sensitivity of the transition to pressure. We also demonstrate that these features allow to obtain these giant and colossal effects in a wide temperature span around room temperature which, furthermore, is desirable for single-component regenerative coolers. The physics underlying these caloric effects is also analysed.