Critical role of the sample preparation in experiments using piezoelectric actuators inducing uniaxial or biaxial strains

Butkovičová, D.; Martí, X.; Saidl, V.; Schmoranzerová-Rozkotová, E.; Wadley, P.; Holý, V.; Němec, Petr

doi:10.1063/1.4823520

Cited by 8 publications

(9 citation statements)

References 14 publications

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“…Strain can be dissipated both in the epoxy layer and in the sample itself. The ability of the stack to transmit the strain to the sample therefore depends on the choice of glue and the thickness and elastic properties of the sample [53]. Previously it was found that the strain is essentially fully transmitted for large (i.e.…”

Section: Practical Considerations: Strain Transmissionmentioning

confidence: 99%

Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors

Kuo¹,

Chu²,

Palmstrom

et al. 2016

Science

327

403

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A key actor in the conventional theory of superconductivity is the induced interaction between electrons mediated by the exchange of virtual collective fluctuations (phonons in the case of conventional s-wave superconductors). Other collective modes that can play the same role, especially spin fluctuations, have been widely discussed in the context of high-temperature and heavy Fermion superconductors. The strength of such collective fluctuations is measured by the associated susceptibility. Here we use differential elastoresistance measurements from five optimally doped iron-based superconductors to show that divergent nematic susceptibility appears to be a generic feature in the optimal doping regime of these materials. This observation motivates consideration of the effects of nematic fluctuations on the superconducting pairing interaction in this family of compounds and possibly beyond.

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Section: Practical Considerations: Strain Transmissionmentioning

confidence: 99%

Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors

Kuo¹,

Chu²,

Palmstrom

et al. 2016

Science

327

403

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show abstract

“…Another source of strain comes from mounting the sample to the piezo stack, which creates a "built-in" strain from the epoxy [35]. To test for the effects of built-in strain, the resistivity as a function of temperature was measured with the sample free-standing and when glued to the piezo stack (Figure 5).…”

Section: Proximity To Strain-induced Transitionmentioning

confidence: 99%

Evidence for a nematic component to the hidden-order parameter in URu2Si2 from differential elastoresistance measurements

et al. 2015

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For materials that harbour a continuous phase transition, the susceptibility of the material to various fields can be used to understand the nature of the fluctuating order and hence the nature of the ordered state. Here we use anisotropic biaxial strain to probe the nematic susceptibility of URu 2 Si 2 , a heavy fermion material for which the nature of the low temperature 'hidden order' state has defied comprehensive understanding for over 30 years. Our measurements reveal that the fluctuating order has a nematic component, confirming reports of twofold anisotropy in the broken symmetry state and strongly constraining theoretical models of the hidden-order phase.

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“…For tetragonal symmetry, the elastoresistivity tensor m ij has six independent coefficients, which can be determined through a combination of elastoresistance measurements using different sample orientations [27]. We use commercially available PZT piezoelectric stacks (PSt150/5x5/7 cryo 1 from Piezomechanik) to generate anisotropic biaxial in-plane strain, following the general method described in Ref.s [27], [28], and [36]. Crystals are glued to the surface of the piezoelectric stack using five minute epoxy (from ITW Devcon), and electrical contact is made using silver paste onto evaporated gold contacts for standard four-point resistance measurements.…”

mentioning

confidence: 99%

Effect of Disorder on the Resistivity Anisotropy Near the Electronic Nematic Phase Transition in Pure and Electron-DopedBaFe2As2

Kuo

Fisher

2014

Phys. Rev. Lett.

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We show that the strain-induced resistivity anisotropy in the tetragonal state of the representative underdoped Fe-arsenides BaFe2As2, Ba(Fe1−xCox)2As2 and Ba(Fe1−xNix)2As2 is independent of disorder over a wide range of defect and impurity concentrations. This result demonstrates that the anisotropy in the in-plane resistivity in the paramagnetic orthorhombic state of this material is not due to elastic scattering from anisotropic defects. Conversely, our result can be most easily understood if the resistivity anisotropy arises primarily from an intrinsic anisotropy in the electronic structure.PACS numbers: 74.70. Xa, Ongoing experimental investigations reveal that the underdoped regime of the cuprate high-temperature superconductors harbors a variety of poorly understood broken symmetry states. In the case of the ferro-pnictide and chalcogenide superconductors, the broken symmetries are much clearer [1], but the physical origin of the phase transitions is still a subject of debate [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Of particular interest, the ferropnictides suffer a tetragonalto-orthorhombic structural transition at a temperature T s that either precedes or accompanies the onset of long range antiferromagnetic magnetic order at T N (see Ref.[19] and references therein). From the perspective of symmetry, all physical properties develop a two-fold inplane anisotropy at such a phase transition. However, the magnitude depends on microscopic details, and therefore measurements that probe the anisotropy in the broken symmetry state can directly or indirectly inform our understanding of the mechanism that drives the phase transition. Quantities such as the in-plane resistivity anisotropy are therefore of considerable interest, and it is especially important to establish intrinsic versus extrinsic effects.In this paper, we show for several representative underdoped Fe-pnictides that the strain-induced resistivity anisotropy in the tetragonal state is independent of the degree of disorder for a given value of T N over a wide range of defect and impurity concentrations. This result can be directly compared to the anisotropy that develops spontaneously in the orthorhombic state (Appendix II) [19][20][21][22][23], and therefore demonstrates that the in-plane resistivity anisotropy observed for this family of compounds in the paramagnetic orthorhombic state is not an extrinsic effect associated with defect scattering. The result can be most easily understood if the resistivity anisotropy in this regime is primarily determined by the Fermi surface anisotropy rather than an anisotropy in the scattering rate.The structural phase transition that occurs in underdoped Fe-pnictides breaks a point symmetry of the original crystal lattice, and hence free-standing crystals naturally form structural twins in order to minimize the elastic energy [19]. The in-plane anisotropy can nevertheless be probed using uniaxial stress to detwin single crystals, as has now been done for several different families [19][20...

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Critical role of the sample preparation in experiments using piezoelectric actuators inducing uniaxial or biaxial strains

Cited by 8 publications

References 14 publications

Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors

Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors

Evidence for a nematic component to the hidden-order parameter in URu2Si2 from differential elastoresistance measurements

Effect of Disorder on the Resistivity Anisotropy Near the Electronic Nematic Phase Transition in Pure and Electron-DopedBaFe2As2

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