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TT: Fachverband Tiefe Temperaturen
TT 100: Frustrated Magnets - Pyrochlore Oxides
TT 100.4: Talk
Thursday, March 15, 2018, 16:15–16:30, H 3005
Inverted hysteresis within the antiferromagnetic all-in-all-out state of the pyrochlore Nd2Hf2O7 — •L. Opherden1,2, T. Bilitewski3, J. Hornung1,2, T. Herrmannsdörfer1, A. Samartzis4,5, A. T. M. N. Islam4, V. K. Anand4, B. Lake4,5, R. Moessner3, and J. Wosnitza1,2 — 1Hochfeld-Magnetlabor Dresden (HLD-EMFL), HZDR, Dresden, Germany — 2Institut für Festkörper- und Materialphysik, TU Dresden, Germany — 3Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany — 4Abteilung Quantenphänomene in neuen Materialien, HZB, Berlin, Germany — 5Institut für Festkörperphysik, TU Berlin, Germany
We report the observation of an anisotropic and inverted hysteresis loop in the antiferromagnetic all-in-all-out ordered phase of Nd2Hf2O7 having a negative remnant magnetization. The hysteresis emerges once exceeding a characteristic magnetic-field strength H⋆(T) below the Neél temperature. The very unusual appearance of a negative remnant magnetization is observed for a field parallel to the [111] and [110] direction. However, for field parallel to [001] no hysteresis can be seen. For this orientation the projection of the field onto all four local spin directions is equal and, hence, both realizations of the all-in-all-out state gaining equal Zeeman energy through a canting of their spins. We show further, that the underlying all-in-all-out phase is established in Nd2Hf2O7 for temperatures below TN = 0.48 K and persists up to fields of 0.27 T. We account for the inverted hysteresis in terms of a theory of uncompensated domain-wall spins of spherical domains forming inside a fully polarized single-domain state.