Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 71: Correlated Electrons: Poster Session

TT 71.38: Poster

Wednesday, March 18, 2015, 15:00–18:00, Poster B

Amorphous ferromagnetism and re-entrant magnetic glassiness in Sm₂Mo₂O₇ — •Giacomo Prando¹, Pietro Carretta², Anja Wolter-Giraud¹, Romuald Saint-Martin³, Alexandre Revcolevschi³, and Bernd Büchner^1,4 — ¹Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden, Germany — ²Dipartimento di Fisica e Unitá CNISM di Pavia, Universitá di Pavia, I-27100 Pavia, Italia — ³Laboratoire de Physico-Chimie de l’Etat Solide, ICMMO, UMR8182, Université Paris-Sud, F-91405 Orsay, France — ⁴Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany

We report on the investigation of a high-quality single crystal of Sm₂Mo₂O₇ by means of dc magnetometry, muon spin spectroscopy and high-harmonics ac susceptibility [1]. The magnetic phase of the Mo⁴⁺ sublattice develops below T_C = 78 K and is typically discussed in the literature as a conventional itinerant ferromagnetic state. However, our results clearly detect a complicated superposition of conventional and highly disordered magnetic behaviors below 78 K sharing several common features with amorphous ferromagnetic alloys and with other insulating spin-glass pyrochlore molybdates. As typical for amorphous ferromagnets, a freezing of the transverse XY spin components of Mo⁴⁺ below T ∼ 25 K is evidenced, an effect otherwise known as re-entrant spin-glass phase. Our results shed new light on the magnetic properties of Sm₂Mo₂O₇ and on the overall electronic phase diagram commonly accepted for pyrochlore molybdates.

[1] G. Prando et al., Phys. Rev. B 90, 085111 (2014)