Magnetic pyroxenes LiCrGe2O6 and LiCrSi2O6: dimensionality crossover in a non-frustrated S=3/2 Heisenberg model

Abstract

The magnetism of magnetoelectric $S$ = 3/2 pyroxenes LiCrSi${}_2$O${}_6$ and LiCrGe${}_2$O${}_6$ is studied by density functional theory (DFT) calculations, quantum Monte Carlo (QMC) simulations, neutron diffraction, as well as low-field and high-field magnetization measurements. In contrast with earlier reports, we find that the two compounds feature remarkably different, albeit non-frustrated magnetic models. In LiCrSi${}_2$O${}_6$, two relevant exchange integrals, $J_1\simeq$ 9 K along the structural chains and $J_{\text{ic1}}$ $\simeq$ 2 K between the chains, form a 2D anisotropic honeycomb lattice. In contrast, the spin model of LiCrGe${}_2$O${}_6$ is constituted of three different exchange couplings. Surprisingly, the leading exchange $J_{\text{ic1}}$ $\simeq$ 2.3 K operates between the chains, while $J_1$ $\simeq$ 1.2 K is about two times smaller. The additional interlayer coupling $J_{\text{ic2}}$ $\simeq$ $J_1$ renders this model 3D. QMC simulations reveal excellent agreement between our magnetic models and the available experimental data. Underlying mechanisms of the exchange couplings, magnetostructural correlations, as well as implications for other pyroxene systems are discussed.

11 pages, 8 figures, 3 tables + Supplementary information

References in corpus (9)

• Spin current and magneto-electric effect in non-collinear magnets
• The ALPS project release 1.3: open source software for strongly correlated systems
• The ALPS project release 2.0: Open source software for strongly correlated systems
• Electronic structure and magnetic properties of pyroxenes (Li,Na)TM(Si,Ge)2O6: novel low-dimensional magnets with 90 bonds
• The role of non-local exchange in the electronic structure of correlated oxides
• Peculiar long-range superexchange in Cu2A2O7 (A = P, As, V) as a key element of the microscopic magnetic model
• Frustrated couplings between alternating spin-1/2 chains in AgVOAsO4
• Magnetic model for A2CuP2O7 (A = Na, Li) revisited: 1D versus 2D behavior
• Structure and magnetism of Cr2BP3O12: Towards the quantum-classical crossover in a spin-3/2 alternating chain

Cited by in corpus (9)

• The planar triangular $S=3/2$ magnet AgCrSe${}_2$: magnetic frustration, short range correlations, and field tuned anisotropic cycloidal magnetic order
• Large magnetocaloric effect in the kagome ferromagnet Li${}_9$Cr${}_3$(P${}_2$O${}_7$)${}_3$(PO${}_4$)${}_2$
• Unravelling the complex magnetic structure of multiferroic pyroxene NaFeGe2O6: A combined experimental and theoretical study
• Successive incommensurate spin orderings and excitations in multiferroic SrMnGe2O6
• Features of magnetic and magnetoelectric properties, H-T phase diagram of GdCr3(BO3)4
• MoP${}_3$SiO${}_{11}$: a $4d^3$ honeycomb antiferromagnet with disconnected octahedra
• Mechanism of ferromagnetic ordering of the Mn chains in CaMnGe${}_2$O${}_6$ clinopyroxene
• Spin dynamics in natural multiferroic pyroxene NaFeSi${}_2$O${}_6$
• Universal fluctuating regime in triangular chromate antiferromagnets