Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 55: Poster II

MA 55.50: Poster

Freitag, 4. April 2014, 10:30–13:30, P2

Metamagnetic transitions in U₂Ni₂Sn probed by high-field magnetization and acoustic measurements — •S. Yasin¹, A.V. Andreev², Y. Skourski¹, S. Zherlitsyn¹, and J. Wosnitza¹ — ¹Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany — ²Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, The Czech Republic

Uranium intermetallic compounds are subjects of intensive fundamental research. The competition between exchange interactions, crystal-field and hybridization effects plays a major role in the formation of 5f magnetic moments and the magnetic ordering. We report on magnetization and ultrasound measurements on antiferromagnet (T_N = 25 K) U₂Ni₂Sn single crystal in pulsed magnetic fields up to 62 T. At T = 1.5 K, three metamagnetic transitions were observed at 30, 40, and 52 T for the magnetic field applied along the c axis. No sign of saturation up to the highest fields was found. Interestingly, the magnetization reaches a value of 1.5 µ_B/f.u. at 60 T which is higher than the uranium magnetic moments (1.05 µ_B at 1.5 K) reported by powder neutron-diffraction. This observation suggests that additional magnetic moments of delocalized electrons are induced by the applied magnetic field. All three metamagnetic transitions are accompanied by pronounced anomalies in the acoustic characteristics. Moreover, in zero magnetic field the sound velocity exhibits an anomaly at T_N. Our results evidence the important role of complex magneto-elastic couplings in this material. The magnetization processes and spin-strain couplings are discussed.