Pressure-Induced Structural Behavior of Orthorhombic Mn₃(VO₄)₂: Raman Spectroscopic and X-ray Diffraction Investigations

Abstract

The effect of high pressure on the structure of orthorhombic Mn3(VO4)2 is investigated using in situ Raman spectroscopy and X-ray powder diffraction up to high pressures of 26.2 and 23.4 GPa, respectively. The study demonstrates a pressure-induced structural phase transition starting at 10 GPa, with the coexistence of phases in the range of 10–20 GPa. The sluggish first-order phase transition is complete by 20 GPa. Importantly, the new phase could be recovered at ambient conditions. Raman spectra of the recovered new phase indicate increased distortion and as a consequence the lowering of the local symmetry of the VO4 tetrahedra. This behavior is different from that reported for isostructural compounds Zn3(VO4)2 and Ni3(VO4)2 where both show stable structures, although almost similar anisotropic compression of the unit cell is observed. The transition observed in orthorhombic Mn3(VO4)2 could be due to the internal charge transfer between the cations, which favors the structural transition at lower pressures and the eventual recovery of the new phase even upon pressure release in comparison to other isostructural compounds. The experimental equation of state parameters obtained for orthorhombic Mn3(VO4)2 match excellently with empirically calculated values reported earlier.

The pressure and temperature evolution of the Ca3V2O8 crystal structure using powder X-ray diffraction

“…19 According to the results summarized above, the HP behavior of Ca 3 V 2 O 8 is different from that of other orthovanadates with equivalent chemical formulae. For instance, Zn 3 V 2 O 8 , Ni 3 V 2 O 8 , and Ba 3 V 2 O 8 remain stable up to at least 15, 20 23 21 and 29 GPa 22 respectively. Mn 3 V 2 O 8 and Sr 3 V 2 O 8 exhibit pressureinduced phase transitions around 10 GPa 23 and 13.8 GPa 22,24 respectively, and Cu 3 V 2 O 8 chemically decomposes at 1.35 GPa.…”

“…For instance, Zn 3 V 2 O 8 , Ni 3 V 2 O 8 , and Ba 3 V 2 O 8 remain stable up to at least 15, 20 23 21 and 29 GPa 22 respectively. Mn 3 V 2 O 8 and Sr 3 V 2 O 8 exhibit pressure-induced phase transitions around 10 GPa 23 and 13.8 GPa 22,24 respectively, and Cu 3 V 2 O 8 chemically decomposes at 1.35 GPa. 25 Such different results from various HP studies in the M 3 V 2 O 8 family, and the apparent contradictions between different HT studies, clearly show that further investigation into the pressure and temperature evolution of the Ca 3 V 2 O 8 is needed to understand its structural behavior under extreme conditions of pressure and temperature.…”

High-Pressure Vibrational and Structural Properties of Ni3V2O8 and Co3V2O8 up to 20 GPa

“…In recent years, the high pressure (HP) community has also put the focus on this family of compounds, which have demonstrated a variety of remarkable physical behaviors under pressure. X-ray diffraction (XRD) and Raman methods were used to study Mn 3 V 2 O 8 in its orthorhombic low-temperature structure; an irreversible phase transition at 10 GPa was discovered, but the new phase has not been identified yet . In contrast, it has been demonstrated that Zn, Ni, and Mg orthovanadates are stable up to 15, 23, and 25.7 GPa, respectively.…”

Comparative Study of the Compressibility of M3V2O8 (M = Cd, Zn, Mg, Ni) Orthovanadates

“…From the fundamental point of view, the high-pressure (HP) behavior of M 3 V 2 O 8 vanadates has also been the focus of recent studies [14][15][16]. X-ray diffraction experiments have shown that Zn 3 V 2 O 8 [14] and Ni 3 V 2 O 8 [15] remain stable in the low-pressure phase up to 15 GPa.…”

“…X-ray diffraction experiments have shown that Zn 3 V 2 O 8 [14] and Ni 3 V 2 O 8 [15] remain stable in the low-pressure phase up to 15 GPa. In Mn 3 V 2 O 8 [16], the onset of a structural phase transition has been located beyond 10 GPa. On the other hand, the bulk moduli of M 3 V 2 O 8 vanadates have been determined to cover a range of values from 100 GPa to 140 GPa.…”