We have measured the specific heat of crystals of (Ca1-xSrx)3Ru2O7 using ac- and relaxation-time calorimetry. Special emphasis was placed on the characterization of the Néel (TN = 56 K) and structural (Tc = 48 K) phase transitions in the pure, x = 0 material. While the latter is believed to be first order, detailed measurements under different experimental conditions suggest that all the latent heat (with L ∼ 0.3 R) is being captured in a broadened peak in the effective heat capacity. The specific heat has a mean-field-like step at TN, but its magnitude (Δ cP ∼ R) is too large to be associated with a conventional itinerant electron (e.g. spin-density-wave) antiferromagnetic transition, while its entropy is too small to be associated with the full ordering of localized spins. The TN transition broadens with Sr substitution while its magnitude decreases slowly. On the other hand, the entropy change associated with the Tc transition decreases rapidly with Sr substitution, and is not observable for our x = 0.58 sample.
|Number of pages||5|
|Journal||Solid State Communications|
|State||Published - Feb 2007|
Bibliographical noteFunding Information:
This research was supported by US National Science Foundation grants DMR-0400938 and DMR-0552267.
- A. Magnetically ordered materials
- D. Heat capacity
- D. Phase transitions
ASJC Scopus subject areas
- Chemistry (all)
- Condensed Matter Physics
- Materials Chemistry