Enhancement of magnetic order in the incommensurate phase of Mg-doped CuGeO${}_3$

Abstract

We present elastic neutron scattering results at high magnetic fields for Mg-doped CuGeO${}_3$. For low magnesium concentrations, where a spin-Peierls phase is present, we find an enhancement of the long range antiferromagnetic order in the structural incommensurate phase induced by a high magnetic field. In the incommensurate phase, the Néel temperature increases with field leading to a gain in the magnetic Bragg peak intensity at low temperatures. We also find that the magnetic Bragg peaks remain commensurate even though the structure is incommensurate at high magnetic fields due to the formation of solitons. We interpret these results in terms of the solitons formed at high-magnetic fields effectively acting as doped impurities. Our results point to a strongly disordered ground state with the the antiferromagnetic order localized around impurity sites.

arXiv comment15 pages, 7 figures

References in corpus (9)

• Impurities in S=1/2 Heisenberg Antiferromagnetic Chains: Consequences for Neutron Scattering and Knight Shift
• Neutron scattering study of the field-induced soliton lattice in CuGeO${}_3$
• The first-order phase transition between dimerized-antiferromagnetic and uniform-antiferromagnetic phases in Cu_(1-x)M_xGeO_3
• Structural Critical Scattering Study of Mg-Doped CuGeO3
• Effects of Disorder on the Competition between Antiferromagnetism and Superconductivity
• Neutron Scattering Study of Temperature-Concentration Phase Diagram of (Cu1-xMgx)GeO3
• Reentrant Spin-Peierls Transition in Mg-Doped CuGeO_3
• Excitations of the field-induced soliton lattice in CuGeO3
• Critical neutron scattering study of the compositional phase transition in Mg-doped CuGeO3

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