Zero-point entropy of the spinel spin glasses CuGa2O4 and CuAl2O4

L. A. Fenner, A. S. Wills, S. T. Bramwell, M. Dahlberg, P. Schiffer

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The zero-point entropy of a spin glass is a difficult property to experimentally determine and interpret. Spin glass theory provides various predictions, including unphysical ones, for the value of the zero-point entropy, however experimental results have been lacking. We have investigated the magnetic properties and zero-point entropy of two spinel Cu2+ based spin glasses, CuGa2O4 and CuAl2O4. Dc- and ac-susceptibility and specific heat measurements show many characteristic spin glass features for both materials. The spin glass freezing temperature is determined to be Tf 2.89 0.05 K for CuGa 2O4 and Tf 2.30 0.05 K for CuAl 2O4. By integrating the specific heat data we have found that CuGa2O4 and CuAl2O4 have zero-point entropies of S0 4.96 JK-1mol-1 and S0 4.76 JK-1mol-1 respectively. These values are closest to the prediction for a Sherrington-Kirkpatrick XY spin glass, however they are notably higher than all of the theoretical predictions. This indicates that CuGa2O4 and CuAl2O4 have a greater degeneracy in their ground states than any of the spin glass models.

Original languageEnglish (US)
Article number012029
JournalJournal of Physics: Conference Series
StatePublished - 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Zero-point entropy of the spinel spin glasses CuGa2O4 and CuAl2O4'. Together they form a unique fingerprint.

Cite this