Three-dimensional magnetic ordering in the quasi-one-dimensional Ising magnetCoNb2O6with partially released geometrical frustration

Abstract

The formation of three-dimensional magnetic ordering has been studied on a quasi-one-dimensional magnet CoNb 2 O 6 by mean-field calculations as well as neutron scattering measurements down to Tϭ1.5 K under magnetic fields up to H ʈ c ϳ600 Oe. Measurements of a deviation of the magnetic Bragg scattering function from the delta function in the ordered state reveal a surprisingly rich variety of the magnetic formation arising from an isosceles triangular arrangement of the magnetic chain with competing interchain interactions in the a-b plane. The competing interactions result in quasidegenerate ground states with different propagation wave numbers along the b* direction in the sinusoidally amplitude-modulated incommensurate magnetic ͑IC͒ phase. Our mean-field calculations qualitatively reproduce the complicated H ʈ c -T magnetic phase diagram and give evidence for a high degeneracy of ground states by calculating the H ʈ c -T dependence of the free energy curve in the propagation wave number space. In addition, a partial cancellation of the exchange field at the apex site from the base sites on the isosceles triangular lattice leads to a quasi-long-range ordering along the a axis in both IC and antiferromagnetic states where the correlation length along the a axis depends on the propagation wave number along the b* direction.

Suppression of magnetic ordering in quasi-one-dimensional FexCo1−xNbSarvezuk1, Kinast2, Colin3 et al. 2011Phys. Rev. B

“…Indeed, the existence of competing antiferromagnetic interactions within a nearly triangular net of ferromagnetic chains in the MNb 2 O 6 structure has been extensively discussed. 5,14,27 The tendency to magnetic frustration of such a structure seems to be enhanced by substitutions like those discussed here.…”

Metamagnetism and soliton excitations in the modulated ferromagnetic Ising chain CoV2O6

“…The zigzag chain material CoNb 2 O 6 is a notable example, showing a transition from spin-density wave order to noncollinear magnetic order on cooling. 7,8 Measurements of physical properties 9,10 and neutron scattering [11][12][13][14][15] under magnetic fields also detect a rich phase diagram which includes regions of three-phase coexistence. 16 Further increases in structural complexity can also produce ground states which are highly sensitive to external perturbations such as magnetic fields.…”

A new approach for the determination of multiple cation locations and ordering, using the example of natural and heat-treated columbites

“…Indeed, the MTa 2 O 6 (M = Fe, Co, Ni) compounds present a two-dimensional antiferromagnetic behaviour (Eicher et al, 1986;Kremer & Greedan, 1998;Kinast et al, 2003Kinast et al, , 2010de Oliveira Neto et al, 2007Reimers et al, 1989;Muraoka et al, 1988), which has been extensively studied in the past few years, whereas the MNb 2 O 6 series of compounds present a one-dimensional ferromagnetic chain antiferromagnetically coupled Yeager, Morrish, Wanklyn & Garrad, 1977;Kobayashi et al, 1999Kobayashi et al, , 2001Hanawa et al, 1994;Heid et al, 1996;Sarvezuk et al, 2011).…”