Publication Date:
2016-09-22
Description:
Author(s): S. Holbein, M. Ackermann, L. Chapon, P. Steffens, A. Gukasov, A. Sazonov, O. Breunig, Y. Sanders, P. Becker, L. Bohatý, T. Lorenz, and M. Braden Although NaFe(WO 4 ) 2 is not multiferroic itself, the magnetic order in this S =5/2 chain material is a reference for many multiferroic materials, such as MnWO 4 and R MnO 3 , because NaFe(WO 4 ) 2 exhibits a transition from an incommensurate spiral order to a commensurate up-up-down-down structure. Here, the authors perform a very extensive study of the magnetic properties in the this double tungstate compound at low temperatures and high magnetic fields. A complex B - T phase diagram is unveiled. Strong magnetoelastic anomalies with a relative contraction of the b lattice parameter of up to 2.6 × 10 − 4 are associated with the up-up-down-down ordering, which appears in the commensurate and also in the anharmonic incommensurate structure. In contrast, the transition to the magnetically ordered phase, with a purely harmonic incommensurate spiral modulation, does not cause resolvable anomalies in the thermal expansion. Thus, the strong magnetoelastic anomaly coupling can be attributed to the lifting of magnetic frustration in the up-up-down-down structure, where neighboring moments align either parallel or antiparallel, although all these bonds are equivalent in the paramagnetic state. [Phys. Rev. B 94, 104423] Published Wed Sep 21, 2016
Keywords:
Magnetism
Print ISSN:
1098-0121
Electronic ISSN:
1095-3795
Topics:
Physics
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