Sawtooth lattice multiferroic BeCr$_2$O$_4$: Non-collinear magnetic structure and multiple magnetic transitions

Hector Cein Mandujano; Alejandro Metta; Neven Barisic; Qiang Zhang; Wojciech Tabis; Naveen Kumar Chogondahalli Muniraju; Harikrishnan S. Nair

doi:10.1103/PhysRevMaterials.7.024422

paper

Sawtooth lattice multiferroic BeCr $_{2}$ O $_{4}$ : Non-collinear magnetic structure and multiple magnetic transitions

arXiv:2303.02806 · doi:10.1103/PhysRevMaterials.7.024422

Abstract

Noncollinear magnetic structures and multiple magnetic phase transitions in a sawtooth lattice antiferromagnet consisting of Cr $^{3 +}$ are experimentally identified in this work, thereby proposing the scenario of magnetism-driven ferroelectricity in a sawtooth lattice. The title compound, BeCr $_{2}$ O $_{4}$ , displays three magnetic phase transitions at low temperatures, at $T_{N 1} \approx$ 7.5 K, at $T_{N 2} \approx$ 25 K and at $T_{N 3} \approx$ 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 \bco\ with two spin-flop-like transitions occurring at $H_{c 1} \approx$ 29 kOe and $H_{c 2} \approx$ 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 $P bnm$ . By performing the magnetic superspace group analysis of the neutron diffraction data at low temperatures, the magnetic structure in the temperature range $T_{N 3, N 2} < T < T_{N 1}$ is determined to be the polar magnetic space group, $P 21 nm . 1^{'} (00 g) 0 s 0 s$ with a cycloidal magnetic propagation vector $k_{1}$ = (0, 0, 0.090(1)). The magnetic structure in the newly identified phase below $T_{N 1}$ , is determined as $P 21/ b . 1^{'} [b] (00 g) 00 s$ with the magnetic propagation vector $k_{2}$ = (0, 0, 0.908(1)). The cycloidal spin structure determined in our work is usually associated with electric polarization, thereby making \bco\ a promising multiferroic belonging to the sparsely populated family of sawtooth lattice antiferromagnets.

arXiv comment24 pages, 5 figures, accepted

Sawtooth lattice multiferroic BeCr $_{2}$ O $_{4}$ : Non-collinear magnetic structure and multiple magnetic transitions

Abstract

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Sawtooth lattice multiferroic BeCr2​O4​: Non-collinear magnetic structure and multiple magnetic transitions

Abstract

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Cited by in corpus (2)

Sawtooth lattice multiferroic BeCr $_{2}$ O $_{4}$ : Non-collinear magnetic structure and multiple magnetic transitions