Regensburg 2013 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster 1
DF 12.68: Poster
Dienstag, 12. März 2013, 10:30–13:30, Poster D
Thermal Expansion and Grüneisen scaling in single-crystalline LiMn1−xNixPO4 — Christopher Dietl1, •Lars Wallbaum1, Kunpeng Wang1, Carsten Jähne1, Herbert Müller3, Hans-Peter Meyer2, and Rüdiger Klingeler1 — 1Kirchhoff Institute for Physics, University of Heidelberg, D-69120 Heidelberg, Germany — 2Institut für Geowissenschaften, University of Heidelberg, D-69120 Heidelberg, Germany — 3Institut für Festkörperphysik, Technische Universität Wien, A-1040 Wien, Austria
Li-based olivine phosphates LiMPO4 (M = Mn, Fe, Co, Ni) exhibit an enormous potential for applications. One the one hand, their electrochemical cyclability and high-temperature stability renders them next-generation cathode materials for Li-ion batteries. In addition, they exhibit complex ordering phenomena, large magnetoelectric effects and unusual ferrotoroidic domains which are supposed to be relevant for data storage applications. In order to study the fundamental properties we have grown LiMn1−xNixPO4 single crystals by the travelling-solvent floating-zone method. Thermal expansion studies along the crystallographic axes by means of capacitive dilatometry imply strong magnetic-elastic coupling. The onset of long-range magnetic order is associated with pronounced lambda-like anomalies in the a- and c-axis thermal expansion and the magnetic specific heat. The data show a strong positive hydrostatic pressure dependence of TN and a large fluctuation regime. The effect of Ni-doping on the magnetic anisotropy as probed by the spin-flop field is discussed.