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arXiv · 1705.02855

Relaxor ferroelectric behavior and intrinsic magnetodielectric behavior near room temperature in Li2Ni2Mo3O12, a compound with distorted honeycomb and spin-chains

Sanjay Kumar Upadhyay·Kartik K Iyer·Shankar Ghosh·P. L. Paulose·E. V. Sampathkumaran
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Abstract

Keeping current interests to identify materials with intrinsic magnetodielectric behavior near room temperature and with novel pyroelectric current anomalies, we report temperature and magnetic-field dependent behavior of complex dielectric permittivity and pyroelectric current for an oxide, Li2Ni2Mo3O12, containing magnetic ions with (distorted) honey-comb and chain arrangement and ordering magnetically below 8 K. The dielectric data reveal the existence of relaxor ferroelectricity behavior in the range 160-240 K and there are corresponding Raman mode anomalies as well in that temperature range. Pyrocurrent behavior is also consistent with this interpretation, with the pyrocurrent peak-temperature interestingly correlating with the poling temperature. 7Li NMR offer an evidence for crystallographic disorder intrinsic to this compound and we therefore conclude that such a disorder is apparently responsible for the randomness of local electric field leading to relaxor ferroelectric property. Another observation of emphasis is that there is a notable decrease in the dielectric constant with the application of magnetic field to the tune of about -2.4% at 300 K, with the magnitude varying mariginally with temperature. Small loss factor values validate intrinsic behavior of the magnetodielectric effect at room temperature.

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Sanjay Kumar Upadhyay, Kartik K Iyer, Shankar Ghosh, P. L. Paulose, E. V. Sampathkumaran. 2017-05-08. Relaxor ferroelectric behavior and intrinsic magnetodielectric behavior near room temperature in Li2Ni2Mo3O12, a compound with distorted honeycomb and spin-chains. https://arxiv.org/abs/1705.02855

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