Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 78: Correlated Electrons: Poster Session
TT 78.21: Poster
Donnerstag, 10. März 2016, 15:00–18:30, Poster D
Magnetization of pyrochlore compounds at mK temperatures — •Lars Opherden1,2, Thomas Herrmannsdörfer1, Jianhui Xu3, Nazmul Islam3, Bella Lake3, and Joachim Wosnitza1,2 — 1Hochfeld-Magnetlabor Dresden, HZDR, Dresden, Germany — 2Institut für Festkörperphysik, TU Dresden, Germany — 3Abteilung Quantenphänomene in neuen Materialien, HZB, Berlin, Germany
Since spin-ice and magnetic-monopole behavior was observed in Ho2Ti2O7 and Dy2Ti2O7, frustrated A2B2O7 (A = rare-earth, B = transition metal) pyrochlores became a highly topical research area [1]. In this material class, magnetic A3+ ions sit on corner-sharing tetrahedra. The crystal electrical fields dominate the interaction. This results in the formation of Kramer doublets and the alignment of the moments along the local ⟨111⟩ direction, if the rare-earth ions have a odd number of unpaired electrons. The balance between dipole-dipole and ferro- or antiferromagnetic exchange interaction leads to the occurrence of highly frustrated magnetism with a variety of ground state configurations such as spin-ice, spin-liquid or all-in-all-out ordering [2]. Because the correlation temperature is mostly observed at T < 1 K, magnetization measurements at millikelvin (mK) temperatures are necessary to investigate these ground states. Here, we present measurements performed in a SQUID magnetometer, designed for the mK temperature range, on novel pyrochlore zirconates A2Zr2O7 (A = Nd, Sm).
[1] S. T. Bramwell et. al., Science 294, 1495 (2001).
[2] J. S. Gardner et. al., Rev. Mod. Phys. 82, 5546 (2010).