Pressure and magnetic field effects on ferroelastic and antiferromagnetic orderings in honeycomb-lattice Mn2V2O7

The multiferroic nature of the honeycomb-lattice Mn2V2O7 was investigated through detailed temperature, high-pressure, and magnetic-field-dependent measurements. A first-order martensiticlike structural phase transition with the thermal hysteresis associated with magnetic, heat-capacity, and dielectric anomalies was observed between TMh (303 K) and TMc (291 K). External pressure up to 15.41 kbar suppresses the thermal hysteresis in the magnetization data, indicating that the high-temperature β-phase persists down to the lower temperature under 15.41 kbar. Furthermore, isothermal capacitance-stress hysteresis loops along with crystallographic Aizu notation of 2/mF1¯ supports a martensitic phase transition driving ferroelastic ordering near or below room temperature. At low temperature, a long-range antiferromagnetic ordering was observed at TN∼17K. With increasing the external pressure up to 15.41 kbar, 100% enhancement of TN was observed and a metamagnetic transition at 5 K was enhanced near 3 T. High-field magnetization study up to 60 T induces multiple metamagnetic transitions below TN. Below TN, a magnetostriction induced magnetoelectric coupling was observed and further supported by the temperature-dependent x-ray studies. Taking these comprehensive research findings into account, we established that Mn2V2O7 is a unique multifunctional material with the coexistence of ferroelastic and antiferromagnetic orderings and with weak magnetoelectric coupling.