[Triumf-seminars] TRIUMF Special Seminar today at 13:00

[TRIUMF Seminars]

Date/Time: Fri 2017-01-13 at 13:00

Location:  Conference Room     

Speaker:   Tathamay Basu (U Augsburg)

Title:     Multiferroicity and magnetoelectric coupling in spin-chain and rare-earth based oxide systems

Abstract: Here, I will discuss the detail magnetoelectric (ME) and multiferroic investigation of two rare-earth (R) based oxide systems, one is Haldane spin-chain system (R2BaNiO5) and another is RCrTiO5 system which forms in well-known multiferroic RMn2O5 structure. Strong ME coupling is observed in heavy rare-earth based Haldane spin-chain system which establishes that geometrical frustration need not be a key factor to result in multiferroicity. One of the major outcomes of this work is that short-range magnetic correlation arising from intra-chain correlations (incipient spin-chain ordering) can in principle trigger ferroelectricity and magnetoelectric coupling under favorable circumstances, even in the bulk form of materials. Therefore, it appears that long range magnetic ordering may not be crucial for ME coupling. The role of rare-earth ion on ME coupling is documented. It is observed that light R- ion (low magnetic moment) is not favorable for strong ME coupling and multiferroicity in case of Haldane system. Interestingly, the role of R-ion in case of RCrTiO5 system is quite intriguing. The compound NdCrTiO5 exhibits magnetism induced ferroelectricity around 21 K. However, no signature of long-range magnetic ordering is observed for the compound GdCrTiO5 down to 2 K, which is unlike. Interesting enough, magnetism induced ferroelectricity is observed around 10 K by an application of magnetic field above 10 kOe for the compound GdCrTiO5. The magnetic behavior of the compound GdCrTiO5 is investigated further through electron-spin-resonance and muSR spectroscopy.

[1] T. Basu, et al., Sci. Rep. 4, 5636 (2014).
[2] K. Singh, T. Basu, et al., Phys. Rev. B 88, 094438 (2013)
[3] T. Basu, et al., J. Phys.: Condens. Matter (Fast Track Communication) 26,172202 (2014)
[4] T. Basu, et al., J. Appl. Phys. 118, 234103 (2015).

Otto Hausser Fellowship Candidate

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