Direct Observation of Re-entrant Multiferroic CuO at High Pressures
| Autor: | Jana, Rajesh, Saha, Pinku, Pareek, Vivek, Basu, Abhisek, Mandal, Guruprasad, Kapri, Sutanu, Bhattacharya, Sayan, Mukherjee, Goutam Dev |
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| Rok vydání: | 2015 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We have carried out a detailed experimental investigation on CuO using dielectric constant, ac resistance, Raman spectroscopy and X-ray diffraction measurements at high pressures and room temperature. Both dielectric constant and dielectric loss show an anomalous peak in the pressure range 3.4-4 GPa indicating a ferroelectric transition. Raman studies show anomalous behaviour of the Ag mode with a slope change in the mode frequency and a minimum in the mode FWHM at 3.4 GPa indicating a strong spin phonon coupling along [1 0 -1] direction. A step like behaviour in the intensity of the Ag mode is observed at 3.4 GPa, indicating a change in the polarization of the mode. A maximum in the intensity of (2,0,-2)Bragg peak at 3.4 GPa points the occurrence of critical scattering due to emergence of magnetic exchange interaction. All our experimental evidences show to the presence of re-entrant type-II multiferroic behaviour in CuO at about 4 GPa. Comment: 21 pages, 8 figures |
| Databáze: | arXiv |
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