Thermodynamic properties of RE2RuO5 (RE = Pr, Nd, Sm, Gd and Tb)

RE2RuO5 (R = Nd, Sm. Eu. Gd. Tb) is anew class of materials. and is found to be insulating and magnetically ordered with an ordering temperature varying from 8 to 21 K. The magnetic ground state is likely to be antiferromagnetic with a canted spin structure that leads to ferromagnetic behavior. The saturation moment is suppressed particularly for Gd2RuO5 and Tb2RuO5. The coefficient of the electronic specific heat for all compounds is conspicuously large ranging from 680 to 800 mJ/mol K-2. All results of this study indicate that the thermodynamic properties are chiefly dominated by 4d-electrons that are strongly coupled through Ru-O-Ru. chains along the b-axis, which largely overwhelms exchange interactions between rare-earth ions. (C) 2001 Published by Elsevier Science B.V.