Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
TT 46.8: Poster
Mittwoch, 18. März 2020, 15:00–19:00, P2/2OG
Investigation of the thermodynamic effects of electron-nucleus interactions in pyrochlores — •J. Gronemann1,2, T. Gottschall1, C. Salazar1, J. Hornung1, T. Herrmannsdörfer1, A. Islam3, V. Anand3, B. Lake3,4, H. Kaneko5, H. Suzuki6, and J. Wosnitza1,2 — 1HLD-EMFL, HZDR, Dresden, Germany — 2Inst. f. Festkörper- und Materialphysik, TU Dresden, Germany — 3Helmholtz-Zentrum Berlin, Germany — 4Inst. f. Festkörperphysik, TU Berlin, Germany — 5Dep. of Quantum Matter, Hiroshima Univ., Japan — 6Dep. of Physics, Kanazawa Univ., Japan
We have investigated selected pyrochlore compounds in order to study possible nuclear magnetic contributions to the formation of their magnetic ground states and unconventional excitations. For that we focused on Ho2Ti2O7 and Pr2Hf2O7. Both are representatives for the occurence of spin-ice behavior.165Ho and 141Pr are isotopically pure elements and have large hyperfine enhanced nuclear magnetic moments. The non-spherical 165Ho nuclei, in addition, carry large electric quadrupole moments. For this reason, these two pyrochlore compounds are well suited to determine possible nuclear magnetic influence. Our specific heat and ac susceptibility data measured at 0.06 K to 10 K suggest a formation of a complex F→ = J→ + I→ coupled ground state which is further modified by electrical field gradients. The ground state F multiplets of Ho2Ti2O7 and Pr2Hf2O7, in consequence, are accompanied by a total entropy which is significantly larger than the one of a purely electronic CEF ground state doublet and in particular larger than the Pauling residual entropy.