Specific Heat of Sr4Ru3O10

TL;DR

This study measures the specific heat of Sr4Ru3O10 single crystals, revealing magnetic anomalies and unusual low-temperature behavior indicative of complex magnetic order and residual heterogeneity.

Contribution

It provides the first detailed specific heat measurements of Sr4Ru3O10, highlighting differences due to growth methods and uncovering unconventional magnetic properties.

Findings

Flux-grown samples show a sharp magnetic transition at 102 K.

Image furnace samples exhibit broader magnetic anomalies.

Low-temperature behavior suggests complex magnetic interactions.

Abstract

We have measured the specific heat of single crystals of the triple-layer Ruddlesden-Popper material, Sr4Ru3O10, grown both in an image furnace and by flux-growth. The flux grown sample has a sharp mean-field-like anomaly at the onset of magnetic order, Tc = 102 K, but a much broader anomaly, indicative of residual heterogeneity, is observed for the image furnace sample. Even for the flux grown sample, however, the anomaly is at least an order of magnitude smaller than one would expect for complete ordering of the spins. Neither sample exhibits an anomaly at Tm ~ 50 K, where magnetic measurements suggest that basal plane antiferromagnetism sets in. Anomalous behavior (e.g. consistent with a term in the specific heat ~ T^3/2 as would be observed for a three-dimensional ferromagnet with weak exchange) is observed at low temperatures for both samples, indicative of the unusual magnetic order in this material.