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arXiv · 1508.02874

Direct Observation of Re-entrant Multiferroic CuO at High Pressures

Rajesh Jana·Pinku Saha·Vivek Pareek·Abhisek Basu·Guruprasad Mandal·Sutanu Kapri·Sayan Bhattacharya·Goutam Dev Mukherjee
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Abstract

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.

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Rajesh Jana, Pinku Saha, Vivek Pareek, Abhisek Basu, Guruprasad Mandal, Sutanu Kapri, Sayan Bhattacharya, Goutam Dev Mukherjee. 2015-08-12. Direct Observation of Re-entrant Multiferroic CuO at High Pressures. https://arxiv.org/abs/1508.02874

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