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TT: Fachverband Tiefe Temperaturen
TT 30: Complex Oxides
TT 30.10: Vortrag
Mittwoch, 29. März 2023, 12:00–12:15, HSZ 204
Magnetoelectric coupling of terbium orthotantalates — •Xiaotian Zhang1, Nicola Kelly2, Cheng Liu1, Sian Dutton1, and Siddharth Saxena1 — 1Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom — 2Department of Chemistry, University of Oxford, Oxford, United Kingdom
Quantum multiferroic materials form a new and emerging area of physics where one expects to find emergence of novel quantum phases induced by subtle coupling between spin and charge degrees of freedom at low temperatures. Experimental study of such phenomena is limited by the lack of model materials where magnetism and dielectric properties can be tuned using magnetic fields at low temperatures.
In a recent breakthrough, we found that TbTaO4 exhibits enhancement in dielectric response below 2 K on application of magnetic field, indicating magnetoelectric coupling. Previously, using susceptibility and heat capacity measurements we showed that TbTaO4 orders at TN = 2.25 K; powder neutron diffraction (PND) was used to solve the magnetic structure, which is A-type antiferromagnetic.
These rare-earth tantalates LnTaO4 (Ln = Y, La-Lu) are of wide interest as a result of their luminescent, proton-conducting, oxide-ion-conducting and dielectric properties. In addition, in the monoclinic M polymorph of the tantalates with Ln = Nd-Er, the magnetic Ln3+ ions are arranged on an elongated diamond lattice. Materials with such a magnetic lattice have the potential for unusual magnetic behaviour owing to the interplay of the crystal electric field with the (possibly competing) J1 and J2 interactions.