Magnetoelastic and thermal effects in the BiMn2O5 lattice: a high-resolution x-ray diffraction study

Abstract

High-resolution synchrotron x-ray diffraction measurements were performed on single crystalline and powder samples of BiMn2O5. A linear temperature dependence of the unit cell volume was found between T_{N}=38$Kand100K,suggestingthatalow-energylatticeexcitationmayberesponsibleforthelatticeexpansioninthistemperaturerange.BetweenT\ast 65Kand{T}_N,alllatticeparametersshowedincipientmagnetoelasticeffects,duetoshort-rangespincorrelations.Ananisotropicstrainalongthea-directionwasalsoobservedbelowT\ast .Below{T}_N,arelativelylargecontractionofthea-parameterfollowingthesquareoftheaveragesublatticemagnetizationofMnwasfound,indicatingthatasecond-orderspinhamiltonianaccountsforthemagneticinteractionsalongthisdirection.Ontheotherhand,themorecomplexbehaviorsfoundfor$b$and$c$ suggest additional magnetic transitions below T_{N} and perhaps higher-order terms in the spin hamiltonian. Polycrystalline samples grown by distinct routes and with nearly homogeneous crystal structure above T_{N} presented structural phase coexistence below T_{N}, indicating a close competition amongst distinct magnetostructural states in this compound.

23 pages, 7 figures

References in corpus (5)

• Coupling of phonons and electromagnons in GdMnO_3
• Ferroelectricity driven by the non-centrosymmetric magnetic ordering in multiferroic TbMn_2O_5: a first-principles study
• Structural Anomalies at the Magnetic and Ferroelectric Transitions in $RM{n}_2{O}_5$ (R=Tb, Dy, Ho)
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Cited by in corpus (1)

• Crystal chemistry aspects of the magnetically induced ferroelectricity in TbMn2O5 and BiMn2O5