Strain relaxation behaviour of vortices in a multiferroic superconductor

Evans, Donald M.; Schiemer, Jason; Wolf, Thomas; Adelmann, P.; Böhmer, Anna E.; Meingast, C.; Dutton, Siân E.; Mukherjee, Paromita; Hsu, Yu-Te; Carpenter, Michael A.

doi:10.1088/1361-648x/aafbd7

Cited by 4 publications

(6 citation statements)

References 91 publications

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“…A small anomaly in linear thermal expansion has been observed within the ab plane of a crystal from the same batch as the present sample [20] and of a crystal with x = 0.045 [48]. There appears to be a similarly small effect parallel to the crystallographic c-axis in a sample with x = 0.055 [48].…”

Section: Elastic Relaxations Associated With Antiferromagnetismsupporting

confidence: 60%

“…The influence of an external magnetic field on the normalsuperconducting transition is considered in detail elsewhere [20]. For present purposes it is sufficient to note that the slight softening with falling temperature at low fields becomes marked stiffening at high fields, accompanied by significant anomalies in Q −1 .…”

Section: Elastic and Anelastic Properties In Applied Magnetic Fieldmentioning

confidence: 95%

“…The implications of the observed elastic and anelastic anomalies are considered in detail in section 6. A more complete description of the strain relaxation behaviour of the superconducting phase, including the contribution of vortices, is presented elsewhere [20].…”

Section: Introductionmentioning

confidence: 99%

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Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂

Carpenter

Evans

Schiemer

et al. 2019

J. Phys.: Condens. Matter

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The hypothesis that strain has a permeating influence on ferroelastic, magnetic and superconducting transitions in 122 iron pnictides has been tested by investigating variations of the elastic and anelastic properties of a single crystal of Ba(Fe 0.957 Co 0.043 ) 2 As 2 by resonant ultrasound spectroscopy as a function of temperature and externally applied magnetic field. Non-linear softening and stiffening of C 66 in the stability fields of both the tetragonal and orthorhombic structures has been found to conform quantitatively to the Landau expansion for a pseudoproper ferroelastic transition which is second order in character. The only exception is that the transition occurs at a temperature (T S ≈ 69 K) ~10 K above the temperature at which C 66 would extrapolate to zero (T * cE ≈ 59 K). An absence of anomalies associated with antiferromagnetic ordering below T N ≈ 60 K implies that coupling of the magnetic order parameter with shear strain is weak. It is concluded that linear-quadratic coupling between the structural/electronic and antiferromagnetic order parameters is suppressed due to the effects of local heterogeneous strain fields arising from the substitution of Fe by Co. An acoustic loss peak at ~50-55 K is attributed to the influence of mobile ferroelastic twin walls that become pinned by a thermally activated process involving polaronic defects. Softening of C 66 by up to ~6% below the normal-superconducting transition at T c ≈ 13 K demonstrates an effective coupling of the shear strain with the order parameter for the superconducting transition which arises indirectly as a consequence of unfavourable coupling of the superconducting order parameter with the ferroelastic order parameter. Ba(Fe 0.957 Co 0.043 ) 2 As 2 is representative of 122 pnictides as forming a class of multiferroic superconductors in which elastic strain relaxations Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.

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Section: Elastic Relaxations Associated With Antiferromagnetismsupporting

confidence: 60%

Section: Elastic and Anelastic Properties In Applied Magnetic Fieldmentioning

confidence: 95%

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Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂

Carpenter

Evans

Schiemer

et al. 2019

J. Phys.: Condens. Matter

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“…[4,5] For instance, naturally occurring structurally sub-nanometer walls-attributed to the presence of mid-gap states, [35] or in VO 2 domain walls around the phase transition, as the new phase nucleates preferentially at ferroelastic domain walls (i.e., a metal state on heating, and an insulating state on cooling). [36] Superconductivity has been reported to appear at structural twin walls before the bulk transition, [37,38] attributed to the local symmetry of the walls and the corresponding strain coupling.…”

Section: Introductionmentioning

confidence: 99%

Strain Driven Conducting Domain Walls in a Mott Insulator

Puntigam

Altthaler

Ghara

et al. 2022

Adv Elect Materials

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wide interfaces, for example, domain walls, have been reported to possess the same inherent electronic response as existing circuit elements, such as switches [6] and half-wave rectifiers. [7] In addition, ferroelectric domain walls can be reconfigured in situ by a variety of external fields which can lead to exotic bulk responses. Such bulk responses offer the opportunity to both enhance existing technology (e.g., magnetoresistance, [8] colossal dielectric constants, [9] memristive behavior [10] ) but also provide next generation functionality like, negative capacitance, [11] above band gap photovoltaic effects, [12] and domain wall nanoelectronics. [13] Such effects have been discussed from both a fundamental and a technological perspective in recent reviews. [14,15] For all of these bulk responses, the key requirement is for the domain walls to exhibit a different conductivity compared to the surrounding material. Therefore, much of the research has focused on ferroelectrics as the build up of screening charges at domain walls with polar discontinuities are known to modify the local conductivity. [13,14] Examples of this, in single crystals, include BaTiO 3 , [16] (Ca,Sr) 3 Ti 2 O 7 , [17] Cu-Cl boracite's, [18] LiNbO 3 , [19] h-RMnO 3 (R representing rare earth metals), [20] and GaV 4 S 8 . [8] Because of the energetically costly nature of such polar discontinuities, their spontaneous formations are normally restricted to improper ferroelectrics. [21,22] Indeed, so established is this screening charge mechanism that it is a surprise for an improper ferroelectric material, exhibiting polar discontinuities, not to have conducting domain walls. [23] In this scenario, the type of domain wall that is expected to have enhanced conductivity depends on the electronic structure of the host material: In a p-type (n-type) semiconductor the tail-to-tail (head-to-head) domain walls attract screening holes (electrons) and thus provide enhanced conductivity relative to the bulk. [24][25][26] The corresponding head-to-head (tail-to-tail) wall in a p-type (n-type) material is then expected to have reduced conductivity compared to the bulk. [13,21,22,27] Note, in ferroelectrics, particularly thin-films, further conductivity mechanisms have been reported. [6,[28][29][30][31][32] But it is challenging, especially in oxides, to disentangle intrinsic effects and those associated with, for example, enhanced defect density at domain walls, [33,34] which can change surface Schottky barriers and hence conductivity. [7] There have also been reports of domain wall conductivity and even superconductivity in non-ferroelectrics. Examples of the former case include, the antiferromagnetic insulators with conducting magnetic domain Rewritable nanoelectronics offer new perspectives and potential to both fundamental research and technological applications. Such interest has driven the research focus into conducting domain walls: pseudo-2D conducting channels that can be created, positioned, and deleted in situ. However, the study of conductive ...

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“…a metal state on heating, and an insulating state on cooling). [36] Superconductivity has reported to appear at structural twin walls before the bulk transition, [37,38] attributed to the local symmetry of the walls and the corresponding strain coupling.…”

Section: Introductionmentioning

confidence: 99%

Strain driven conducting domain walls in a Mott insulator

Puntigam¹,

Altthaler²,

Ghara³

et al. 2022

Preprint

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Rewritable nanoelectronics offers new perspectives and potential to both fundamental research and technological applications. Such interest has driven the research focus into conducting domain walls: pseudo-2D conducting channels that can be created, positioned, and deleted in-situ. However, the study of conductive domain walls is largely limited to wide-gap ferroelectrics, where the conductivity typically arises from changes in charge carrier density, due to screening charge accumulation at polar discontinuities. This work shows that, in narrow-gap correlated insulators with strong chargelattice coupling, local strain gradients can drive enhanced conductivity at the domain walls -removing polar-discontinuities as a criteria for conductivity. By combining different scanning probe microscopy techniques, we demonstrate that the domain wall conductivity in GaV 4 S 8 does not follow the established screening charge model but rather arises from the large surface reconstruction across the Jahn-Teller transition and the associated strain gradients across the domain walls. This mechanism can turn any structural, or even magnetic, domain wall conducting, if the electronic structure of the host is susceptible to local strain gradients -drastically expanding the range of materials and phenomena that may be applicable to domain wall-based nanoelectronics.

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Strain relaxation behaviour of vortices in a multiferroic superconductor

Cited by 4 publications

References 91 publications

Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂

Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂

Strain Driven Conducting Domain Walls in a Mott Insulator

Strain driven conducting domain walls in a Mott insulator

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Strain relaxation behaviour of vortices in a multiferroic superconductor

Cited by 4 publications

References 91 publications

Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe0.957Co0.043)2As2

Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe0.957Co0.043)2As2

Strain Driven Conducting Domain Walls in a Mott Insulator

Strain driven conducting domain walls in a Mott insulator

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Product

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Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂

Ferroelasticity, anelasticity and magnetoelastic relaxation in Co-doped iron pnictide: Ba(Fe_0.957Co_0.043)₂As₂