We introduce a model compound featuring a spin-1/2 frustrated square lattice partially coupled by spin-5/2. A significant magnetization plateau exceeding 60 T could be observed, indicating a quantum state formed by S = 1/2 spins in the square lattice. The remaining S = 5/2 spins exhibited paramagnetic behavior in the low-field regions. The numerical analysis confirmed that the observed quantum state is a many-body entangled state based on the dominant AF interactions and is strongly stabilized by coupling with spin-5/2. The stabilization of this quantum state can be attributed to a compensation effect similar to magnetic field-induced superconductivity, which serves as a strategy to control the stability of quantum spin states in magnetic fields.
@article{arxiv.2404.06767,
title = {Quantum spin state stabilized by coupling with classical spins},
author = {Hironori Yamaguchi and Tsuyoshi Okubo and Akira Matsuo and Takashi Kawakami and Yoshiki Iwasaki and Taiki Takahashi and Yuko Hosokoshi and Koichi Kindo},
journal= {arXiv preprint arXiv:2404.06767},
year = {2024}
}