Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 25: Correlated Electrons: Frustrated Magnets - Strong Spin-Orbit Coupling 1
TT 25.13: Talk
Tuesday, March 21, 2017, 12:45–13:00, HSZ 304
Frustrated magnetism and Kitaev exchange on the fcc lattice of K2IrCl6 — •Nazir Khan and Alexander A. Tsirlin — EP VI, EKM, Augsburg University, 86159 Augsburg, Germany
Face-centered cubic lattice (fcc) is inherently frustrated, whereas Ir4+ ion brings the possibility of Kitaev anisotropy. Synchrotron x-ray study on the powder sample of K2IrCl6 shows that the compound retains its room temperature fcc structure (space group Fm-3m) and symmetrical Cl6 octahedral environment down to the low temperature of 20 K followed by 3% volume collapse of the unit cell. Temperature and field dependence of magnetization show that the compound undergoes a paramagnetic to an antiferromagnetic phase transition at TN=3.14 K. The Curie-Weiss fitting to the high temperature data yields an effective magnetic moment µeff=1.69 µB/Ir ion and Curie-Weiss temperature θCW=−41.0 K. The frustration parameter, f=|θCW|/TN, is found to be 13.0 which suggests presence of significant magnetic frustration. The temperature dependence of electrical resistivity shows that the compound is an insulator with a charge gap close to 0.7 eV.