EuCd2P2 is notable for its unconventional transport: upon cooling the metallic resistivity changes slope and begins to increase, ultimately 100-fold, before returning to its metallic value. Surprisingly, this giant peak occurs at 18K, well above the N\'{e}el temperature (TN) of 11.5K. Using a suite of sensitive probes of magnetism, including resonant x-ray scattering and magneto-optical polarimetry, we have discovered that ferromagnetic order onsets above TN in the temperature range of the resistivity peak. The observation of inverted hysteresis in this regime shows that ferromagnetism is promoted by coupling of localized spins and itinerant carriers. The resulting carrier localization is confirmed by optical conductivity measurements.
@article{arxiv.2208.05499,
title = {Spin-carrier coupling induced ferromagnetism and giant resistivity peak in EuCd$_2$P$_2$},
author = {Veronika Sunko and Yue Sun and Mayia Vranas and Christopher C. Homes and Changmin Lee and Elizabeth Donoway and Zhi-Cheng Wang and Sudhaman Balguri and Mira B. Mahendru and Alejandro Ruiz and Brandon Gunn and Rourav Basak and Enrico Schierle and Eugene Weschke and Fazel Tafti and Alex Frano and Joseph Orenstein},
journal= {arXiv preprint arXiv:2208.05499},
year = {2023}
}