Comment on "Unconventional enhancement of ferromagnetic interactions in Cd-doped GdFe2Zn20 single crystals studied by ESR and 57Fe Mossbauer spectroscopies"

TL;DR

This paper challenges previous claims by Cabrera-Baez et al. that Cd-doping significantly reduces Gd magnetic moments in GdFe2Zn20, showing instead that the moments remain largely unchanged despite a modest increase in Curie temperature.

Contribution

The authors refute prior findings by reproducing the samples and measurements, demonstrating no significant reduction in Gd moments due to Cd substitution.

Findings

No significant reduction in Gd effective or saturated moments with Cd doping

Modest increase in Curie temperature (T_C) with Cd substitution

Reproducibility of magnetic properties contradicts previous reports

Abstract

In the recent publication, Phys. Rev. B 102, 144420 (2020), Cabrera-Baez et al. present a study of the effects of Cd-substitution for Zn in the ferromagnetic compound GdFe2Zn20. As part of this paper, they claim that for GdFe2Zn18.6Cd1.4 the effective moment of Gd is reduced by 25% and the saturated moment of Gd is reduced by over 40%. We regrew representative members of the GdFe2Zn(20-x)Cdx series and did not find any such reductions. In addition, we measured several crystals from the growth batch that was used by Cabrera-Baez et al. and did not see such reductions. Although there is a modest increase in TC with Cd substitution, there is no significant change in the Gd effective moment or the saturated moment associated with the low temperature ferromagnetic state.