Pressure induced structural phase transition in Cr doped Mn2O3 multiferroics

Abstract

The pressure dependent structural properties of polycrystalline Mn2−xCrxO3 (x = 0, 0.01, 0.05) multiferroics have been investigated using synchrotron x-ray diffraction (SXRD) measurements up to 41 GPa at room temperature (RT). Our results illustrate that irrespective of their RT crystal structure, all the studied samples undergo pressure induced structural phase transition to monoclinic phase. For pristine Mn2O3, the phase transition starts around 20.8 GPa and completely transformed to monoclinic phase around 37 GPa during compression. The co-existence of orthorhombic and monoclinic phase persists at wide pressure range i.e. 20.8 to 37 GPa. The Cr substitutions lower the required pressure for pressure induced phase transition i.e. for x = 0.01 and x = 0.05, Cr doped samples, the pressure induced phase transition occurs at 35 GPa and 33 GPa, respectively. These transitions are reversible (with hysteresis) during decompression and remained unquenchable under pressure. These results corroborate that Cr substitution modify the RT crystal structure and induces positive chemical pressure in Mn2O3.