Observation of room-temperature ferroelectricity in spark-plasma sintered GdCrO3
| Autor: | Suryakanta Mishra, Aminur Rahaman, Pratap Pal, Archna Sagdeo, Debraj Choudhury, Dinesh Topwal, Krishna Rudrapal, Ranjit Mishra, Ayan Roy Chaudhuri, Keerthana, Venimadhav Adyam |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Physical Review B. 104 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | A spark-plasma sintered ${\mathrm{GdCrO}}_{3}$ (SPS-GCO) is found to stabilize in its ferroelectric phase beyond room temperature. The intrinsic nature of this room-temperature ferroelectricity is established using ferroelectric positive-up--negative-down measurements and supported through piezoresponce force microscopy measurements. The SPS-GCO undergoes antiferromagnetic ordering at much lower temperatures, only below $\ensuremath{\approx}170\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. Thus, any role of magnetism to the observed room temperature ferroelectricity in SPS-GCO can be ruled out. This is contrast to the concomitant antiferromagnetic and ferroelectric ordering observed below $\ensuremath{\approx}170\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ in ${\mathrm{GdCrO}}_{3}$ (GCO) (prepared using standard solid-state synthesis technique). Using detailed Rietveld refinements of room-temperature x-ray diffraction patterns, SPS-GCO is found to stabilize in the noncentrosymmetric orthorhombic $Pna{2}_{1}$ space group (the reported low-temperature ferroelectric phase in GCO), while GCO stabilizes in the centrosymmetric $Pbnm$ space group at room temperature. Using first-principles calculations, we investigated the relative energies among various possible structures of ${\mathrm{GdCrO}}_{3}$ and found that the orthorhombic $Pna{2}_{1}$ and $Pbnm$ space groups are the most stable structures. The ferroelectric $Pna{2}_{1}$ phase of SPS-GCO (stabilized at room temperature using the high-pressure and high-temperature spark-plasma sintering process) undergoes transition to the paraelectric centrosymmetric phase upon heating beyond $\ensuremath{\approx}450\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ (as confirmed using dielectric and calorimetric measurements), which on subsequent cooling to room temperature does not undergo a transition back to the ferroelectric phase and remains in the centrosymmetric $Pbnm$ phase. |
| Databáze: | OpenAIRE |
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