Pressure-Induced Volume Collapse and Metallization in Inverse Spinel Co$_2$TiO$_4$
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arXiv
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| Autori principali: | , , , , , , |
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| Natura: | Preprint |
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2025
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| _version_ | 1866913916216410112 |
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| author | Sahu, Mrinmay Chakraborty, Souvick Mukherjee, Bidisha Ghosh, Bishnupada Mishra, Asish Kumar Raj, Satyabrata Mukherjee, Goutam Dev |
| author_facet | Sahu, Mrinmay Chakraborty, Souvick Mukherjee, Bidisha Ghosh, Bishnupada Mishra, Asish Kumar Raj, Satyabrata Mukherjee, Goutam Dev |
| contents | The structural, vibrational, electronic, and magnetic properties of inverse spinel $Co_2TiO_4$ (CTO-Sp) under high-pressure (HP) conditions are systematically investigated using X-ray diffraction, Raman spectroscopy, in situ optical microscopy, and first-principles density functional theory (DFT) calculations. At ambient conditions, CTO-Sp exhibits a cubic phase with a space group $Fd\bar{3}m$, and it undergoes two notable structural phase transitions at HP. The first transition, occurring at approximately 7.3 GPa, leads to the tetragonal-$I4_1/amd$ phase with minimal alteration in unit cell volume. {The second transition takes place near 17.3 GPa, where two orthorhombic phases emerge and coexist above this pressure.} This second structural transition corresponds to a first-order phase transition involving a significant reduction in unit cell volume of approximately 17.5$\%$. The bulk compressibility of CTO-Sp and its HP post-spinel phases is almost equal to the average polyhedral compressibility within each phase. DFT calculations reveal a high-spin to low-spin transition, accompanied by the collapse of local magnetic moments in the $Cmcm$ orthorhombic phase, leading to the sample's pressure-induced metallization. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_00574 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Pressure-Induced Volume Collapse and Metallization in Inverse Spinel Co$_2$TiO$_4$ Sahu, Mrinmay Chakraborty, Souvick Mukherjee, Bidisha Ghosh, Bishnupada Mishra, Asish Kumar Raj, Satyabrata Mukherjee, Goutam Dev Materials Science The structural, vibrational, electronic, and magnetic properties of inverse spinel $Co_2TiO_4$ (CTO-Sp) under high-pressure (HP) conditions are systematically investigated using X-ray diffraction, Raman spectroscopy, in situ optical microscopy, and first-principles density functional theory (DFT) calculations. At ambient conditions, CTO-Sp exhibits a cubic phase with a space group $Fd\bar{3}m$, and it undergoes two notable structural phase transitions at HP. The first transition, occurring at approximately 7.3 GPa, leads to the tetragonal-$I4_1/amd$ phase with minimal alteration in unit cell volume. {The second transition takes place near 17.3 GPa, where two orthorhombic phases emerge and coexist above this pressure.} This second structural transition corresponds to a first-order phase transition involving a significant reduction in unit cell volume of approximately 17.5$\%$. The bulk compressibility of CTO-Sp and its HP post-spinel phases is almost equal to the average polyhedral compressibility within each phase. DFT calculations reveal a high-spin to low-spin transition, accompanied by the collapse of local magnetic moments in the $Cmcm$ orthorhombic phase, leading to the sample's pressure-induced metallization. |
| title | Pressure-Induced Volume Collapse and Metallization in Inverse Spinel Co$_2$TiO$_4$ |
| topic | Materials Science |
| url | https://arxiv.org/abs/2504.00574 |