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MA: Fachverband Magnetismus
MA 37: Frustrated Magnets - Strong Spin-Orbit Coupling 2 (joint session TT/MA)
MA 37.4: Vortrag
Mittwoch, 18. März 2020, 15:45–16:00, HSZ 304
New phases in the Shastry-Sutherland compound NdB4 discovered by high-resolution dilatometry — •Rahel Ohlendorf1, Sven Spachmann1, Daniel Brunt2, Oleg Petrenko2, and Rüdiger Klingeler1 — 1Kirchhoff Institute for Physics, Heidelberg, Germany — 2Department of Physics, University of Warwick, UK
We report detailed thermal expansion and magnetostriction studies on NdB4 single crystals in magnetic fields up to 15 T. The system can be mapped on a Shastry-Sutherland model implying magnetically frustrated orthogonal dimers of Nd-moments. Accordingly, a sequence of unusual magnetic phases has been reported [1]. At B=0 T these phases are associated with the evolution of antiferromagnetic (afm) order at T1=17.2 K and two incommensurate afm phases at T2=7.0 K and T3=4.8 K. All transitions are associated with pronounced anomalies in the thermal expansion coefficients which enables studying the phase boundaries in external magnetic fields, here applied along the crystallographic [001]- and [110]-axis, respectively. Our data confirm previously reported phase boundaries and show, e.g., that the nature of the phase transition T2(B) changes from continuous to discontinuous. In addition, for each field direction our data evidence novel phases not reported before. The phase diagram is discussed based on the anomalies in the thermal expansion and magnetostriction data and the respective uniaxial pressure dependencies.
[1] Ryuta Watanuki et al 2009 J. Phys.: Conf. Ser. 150 042229