Emergent 1/3 magnetization plateaus in pyroxene CoGeO\(_3\)

• Published in: arXiv.org
• Main Authors: Guo, H, Zhao, L, Baenitz, M, Fabrèges, X, Gukasov, A, A Melendez Sans, Khomskii, D I, Tjeng, L H, Komarek, A C
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 15.09.2021
• Subjects: Antiferromagnetism; Chains; Crystal structure; Domain walls; Ferromagnetism; Ising model; Magnetic structure; Magnetism; Magnetization; Neutron diffraction; Pyroxenes; Spin structure
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2109.07367

Despite the absence of an apparent triangular pattern in the crystal structure, we observe unusually well pronounced 1/3 magnetization plateaus in the quasi one-dimensional Ising spin chain compound CoGeO\(_3\) which belongs to the class of pyroxene minerals. We succeeded in uncovering the detailed microscopic spin structure of the 1/3 magnetization plateau phase by means of neutron diffraction. We observed changes of the initial antiferromagnetic zero-field spin structure that are resembling a regular formation of antiferromagnetic "domain wall boundaries", resulting in a kind of modulated magnetic structure with 1/3-integer propagation vector. The net ferromagnetic moment emerges at these "domain walls" whereas two third of all antiferromagnetic chain alignments can be still preserved. We propose a microscopic model on the basis of an anisotropic frustrated square lattice to explain the observations.