Sawtooth lattice multiferroic BeCr2O4: Noncollinear magnetic structure and multiple magnetic transitions

Scientific paper - Original scientific paper

• Author: Hector Cein Mandujano
• Author: Alejandro Metta
• Author: Neven Barišić
• Author: Qiang Zhang
• Author: Wojciech Tabiś
• Author: Naveen Kumar Chogondahalli Muniraju
• Author: Harikrishnan S. Nair
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Noncollinear magnetic structures and multiple magnetic phase transitions in a sawtooth lattice antiferromagnet consisting of Cr3+ are experimentally identified in this work, thereby proposing the scenario of magnetism-driven ferroelectricity in a sawtooth lattice. The title compound, BeCr2O4, displays three magnetic phase transitions at low temperatures—at TN1≈7.5 K, at TN2≈25 K, and at TN3≈26 K—revealed through magnetic susceptibility, specific heat, and neutron diffraction in this work. These magnetic phase transitions are found to be influenced by externally applied magnetic fields. Isothermal magnetization curves at low temperatures below the magnetic transitions indicate the antiferromagnetic nature of BeCr2O4 with two spin-flop-like transitions occurring at Hc1≈29 kOe and Hc2≈47 kOe. Our high-resolution x-ray and neutron diffraction studies, performed on single crystal and powder samples, unambiguously determined the crystal structure as orthorhombic Pbnm. By performing the magnetic superspace group analysis of the neutron diffraction data at low temperatures, the magnetic structure in the temperature range TN3,N2<T<TN1 is determined to be the polar magnetic space group P21nm.1′(00g)0s0s with a cycloidal magnetic propagation vector k1=(0,0,0.090(1)). The magnetic structure in the newly identified phase below TN1 is determined as P21/b.1′[b](00g)00s with the magnetic propagation vector k2=(0,0,0.908(1)). The cycloidal spin structure determined in our work is usually associated with electric polarization, thereby making BeCr2O4 a promising multiferroic belonging to the sparsely populated family of sawtooth lattice antiferromagnets.

• Keywords (english): sawtooth lattice; noncollinear magnetic structure; multiple magnetic transitions
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review Materials
• Numbering: vol. 7, no. 2, 024422
• e-ISSN: 2475-9953
• DOI: https://doi.org/10.1103/PhysRevMaterials.7.024422
• URN:NBN: urn:nbn:hr:217:774838
• Publication: 2023
• Project: Number: IP-2020-02-9666; Title (croatian): Interkalirani Dihalkogenidi Prijelaznih Metala; Title (english): Intercalated Transition Metal Dichalcogenides; Acronym: iTMD; Leader: Petar Popčević; Jurisdiction: Croatia; Funding stream: IP
• Project: Number: KK.01.1.1.02.0012; Title (english): Cryogenic Centre at the Institute of Physics; Acronym: KaCIF; Leader: Nikolina Novosel; Jurisdiction: eu
• Document URL: https://link.aps.org/doi/10.1103/PhysRevMaterials.7.024422
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2023 American Physical Society. Received 13 December 2022; Accepted 13 February 2023; Corrected 10 July 2023; Published 28 February 2023.
• Created on: 2023-08-23 12:47:33