### Session Q34: Focus Session: Frustrated and Low-D Magnetism -- Spins, Orbitals, and Phonons

11:15 AM–2:15 PM, Wednesday, March 17, 2010
Room: E144

Chair: Joachim Deisenhofer, Augsburg University

Abstract ID: BAPS.2010.MAR.Q34.1

### Abstract: Q34.00001 : Probing spin correlations in the frustrated magnets CdCr$_2$O$_4$ and ZnCr$_2$O$_4$

11:15 AM–11:27 AM

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#### Authors:

Joachim Deisenhofer
Christian Kant
Franz Mayr
Florian Schrettle
Torsten Rudolf
Valdimir Tsurkan
Alois Loidl
(Experimentalphysik V, Center for Electronic Correlations and Magnetism, Institute for Physics, Augsburg University, D-86135 Augsburg, Germany)

We performed optical, magnetic susceptibility, and specific heat measurements on CdCr$_2$O$_4$ and ZnCr$_2$O$_4$ single crystals. We estimate the nearest-neighbor and next-nearest neighbor exchange constants from the magnetic susceptibility and extract the spin-spin correlation functions obtained from the magnetic susceptibility and the magnetic contribution to the specific heat. In comparison with the frequency shift of the infrared optical phonons above $T_N$, we can obtain estimates for the spin-phonon coupling in both systems. Moreover, we will discuss optical signatures of the magnetic excitation spectrum which are found to persist up to room temperature in ZnCr$_2$O$_4$.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.Q34.1