We have studied the magnetoelectric coupling of the frustrated triangular antiferromagnet iron jarosite using Raman spectroscopy, dielectric measurements and specific heat. Temperature dependent capacitance measurements show an anomaly in the dielectric constant at T-N. Specific heat data indicate the presence of a low frequency Einstein mode at low temperature. Raman spectroscopy confirms the presence of a new mode below T-N that can be attributed to folding of the Brillouin zone. This mode shifts and sharpens below T-N. We evaluate the strength of the magnetoelectric coupling using the symmetry unrestricted biquadratic magnetoelectric terms in the free energy. (C) 2012 Elsevier Inc. All rights reserved.
- Phonon mode
- Frustrated triangular antiferromagnet