Evolution of ferroelectric and antiferromagnetic phases of TbMn2O5 under high magnetic field up to 45 T

초록

We determine high magnetic field (B//a) vs temperature phase diagram of TbMn2O5 by measurements of dielectric constant (epsilon//b) and magnetization under static and pulsed B up to 45 T, and pyroelectric/magnetoelectric currents up to 9 T. Our results reveal that a ferroelectric (FE) transition temperature at T-C = 38 K at B = 0 T changes little under B up to 33 T, while incommensurate antiferromagnetic phase, characterized as increased e and negative polarization below 25 K at B = 0 T, becomes unstable above B = similar to 20 T at low temperatures. Furthermore, a positive FE polarization component, coined with a Tb f-spin ordering below similar to 15 K at B = 0 T, abruptly disappears with Tb f- spin reorientation under B = similar to 2 T. Determined phase diagram shows that both magnitude of FE polarization and e value are sensitively dependent on the evolution of magnetic order parameters of both Mn-d and Tb-f spins tuned by high magnetic fields.

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