Novel reduction of hysteresis loss controlled by strain memory effect in FeRh/PMN-PT heterostructures

Abstract

As living standards increase, the energy consumption in refrigeration, such as air-conditioning and refrigerators, tremendously increases and intensifies global warming. As an alternative for the conventional vapor compression technique, solid state refrigeration based on magnetocaloric effect shows significant potential due to energy-saving and environmental-friendly properties. However, hysteresis loss is a longstanding problem seriously harming refrigeration efficiency. Here, we report novel enhancement of refrigeration efficiency controlled by strain memory effect in FeRh films grown on (011)-PMN-PT substrates. Utilizing nonvolatile strain triggered by a pulse electric field to engineer magnetization process of FeRh film, a nonvolatile large reduction of hysteresis loss, ∼56%, is achieved, consequently effective refrigeration capacity increases to ∼86%. The hysteresis loss can be expected to be eliminated and even turned out to be inverse through enhancing the strain memory effect. As a result, effective refrigeration capacity (RCeffe) can increase to a new height through introducing external mechanical work in a magnetic refrigeration cycle, and the ideal COP (coefficient-of-performance) would break through Carnot limit if only hysteresis loss and the contribution of mechanical work were considered.