The layered perovskite Sr2RuO4 is a most intensively studied superconductor, but its pairing mechanism, which is often coupled intimately with magnetic fluctuations in correlated materials, is still an open question. Here we present a systematic evolution of the Seebeck coefficient in Co- and Mn-substituted Sr2RuO4 single crystals, in which ferromagnetic and antiferromagnetic glassy states respectively emerge in proximity to the superconducting phase of the parent compound. We find that the Seebeck coefficient S divided by temperature T, S/T, shows a maximum near characteristic temperatures seen in the irreversible magnetization Mir in both of the Co- and Mn-substituted crystals, demonstrating both of the ferromagnetic and antiferromagnetic fluctuations to enhance the Seebeck coefficient. Interestingly, S/T increases with lowering temperature in the parent compound, reminiscent of non-Fermi-liquid behavior, indicating an essential role of coexisting ferromagnetic and antiferromagnetic fluctuations for the itinerant electrons in Sr2RuO4.
@article{arxiv.2205.00599,
title = {Enhanced Seebeck coefficient through the magnetic fluctuations in Sr$_2$Ru$_{1-x}M_x$O$_4$ ($M = $ Co, Mn)},
author = {Takayoshi Yamanaka and Ryuji Okazaki and Hiroshi Yaguchi},
journal= {arXiv preprint arXiv:2205.00599},
year = {2022}
}