Dilatometry under high pressure

Fietz, W.H.; Grube, K.; Leibrock, H.

doi:10.1080/08957950008202580

Cited by 8 publications

(7 citation statements)

References 3 publications

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“…The conversion from stress to strain dependences does not qualitatively change the overall behavior of CeCu6-xAux as can be checked if all cij are known. We therefore have determined the remaining elastic constants c12, c13, and c23 by employing measurements of the linear compressibilities /  = −  ii kp (with i = a,b,c in Voigt's notation) by using a miniaturized capacitive dilatometer built into a gas pressure cell 29,30…”

Section: =1mentioning

confidence: 99%

Multidimensional entropy landscape of quantum criticality

et al. 2017

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The third law of thermodynamics states that the entropy of any system in equilibrium has to vanish at absolute zero temperature. At nonzero temperatures, on the other hand, matter is expected to accumulate entropy near a quantum critical point, where it undergoes a continuous transition from one ground state to another 1,2 . Here, we determine, based on general thermodynamic principles, the spatial-dimensional profile of the entropy S near a quantum critical point and its steepest descent in the corresponding multidimensional stress space. We demonstrate this approach for the canonical quantum critical compound CeCu 6−x Au x near its onset of antiferromagnetic order 2 . We are able to link the directional stress dependence of S to the previously determined geometry of quantum critical fluctuations 3 . Our demonstration of the multidimensional entropy landscape provides the foundation to understand how quantum criticality nucleates novel phases such as high-temperature superconductivity.Quantum criticality arises near a second-order phase transition that is driven to zero temperature by competing interactions. For metallic systems, it provides a mechanism to generate new types of electron-derived excitations that are distinct from Landau's Fermi liquid 2 . Because quantum fluctuations are enhanced when the dimensionality is reduced, quantum critical points (QCPs) often arise in anisotropic systems. The quantum critical fluctuations lead to unconventional scaling behaviour and the accumulation of entropy at very low T , thereby allowing unusual electronic excitations and new phases. The enhanced entropy S upon approaching a QCP has been probed by measurements of the specific heat, and its dependence on pressure was studied by volume thermal expansion. The entropy landscape has been studied up to now using a single tuning parameter 4 . To understand how entropy evolves as the system traverses near a QCP, exploration of its profile in a multidimensional parameter space is needed.Heavy-fermion systems represent prototype settings for QCPs induced by pressure. The latter tunes the hybridization of the almost localized 4f states with the conduction band, thereby tilting the balance in the competition between Ruderman-Kittel-Kasuya-Yosida (RKKY) and Kondo interactions. Previous experiments on quantum critical heavy-fermion systems 5,6 focused on the volume expansivity α V and volume Grüneisen ratio Γ V . Both α V /T and Γ V were found to diverge as T → 0, indicating a diverging pressure dependence of S and a vanishing energy scale near the QCP, as predicted 7 . Spatial anisotropy, a hallmark of many heavy-fermion systems, allows a QCP to be accessed with multiple tuning parameters.Here we show that, for anisotropic systems, the directional dependence of the thermal expansivity provides a means to determine the spatial-dimensional profile of the thermodynamic singularities near a QCP. We establish a procedure to identify the combination of stresses that aims directly at the QCP and accomplishes the steepest change of the...

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Section: =1mentioning

confidence: 99%

Multidimensional entropy landscape of quantum criticality

et al. 2017

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“…[88]. However, by changing the starting capacitance and taking into account the contact area between the dilatometer and the sample, one can perform quasi-uniaxial thermal expansion experiments under pressures up to ∼100 bar employing the above-described setup, see e.g.…”

Section: Thermal Expansion Measurements Under Quasi-uniaxial Pressurementioning

confidence: 99%

Probing the Mott physics inκ-(BEDT-TTF)₂X salts via thermal expansion

Souza

Bartosch

2015

J. Phys.: Condens. Matter

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In the field of interacting electron systems the Mott metal-to-insulator (MI) transition represents one of the pivotal issues. The role played by lattice degrees of freedom for the Mott MI transition and the Mott criticality in a variety of materials are current topics under debate. In this context, molecular conductors of the κ-(BEDT-TTF) 2 X type constitute a class of materials for unraveling several aspects of the Mott physics. In this review, we present a synopsis of literature results with focus on recent expansivity measurements probing the Mott MI transition in this class of materials. Progress in the description of the Mott critical behavior is also addressed.

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“…[3]). On the other hand, the relatively high 'pressure volume' of the piston-cylinder assembly allows not only to put inside the cell the sample itself, but use the complete measurement setup as is made, e.g., for resistivity [3][4][5], ac-suspeptibility [6], nuclear magnetic resonance [7], specific heat [8], tunneling [9], ultrasound [10], thermal expansion experiments [11], etc. A reasonably large volume sample chamber and relatively small pressure cell CONTACT Rustem Khasanov.…”

Section: Introductionmentioning

confidence: 99%

Three-wall piston-cylinder type pressure cell for muon-spin rotation/relaxation experiments

Khasanov,

Urquhart,

Elender

et al. 2021

Preprint

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A three-wall piston-cylinder type high pressure cell for muon-spin rotation/relaxation experiments was designed, manufactured, tested and commissioned. The outer cylinder of the cell body is made from MP35N and the middle and the inner cylinders are made from NiCrAl nonmagnetic alloys. The mechanical design and performance of the pressure cell are evaluated and optimised using finite-element analysis. The outcomes of the experimental testing closely match the modelling results. The high-pressure cell is shown to reach pressures of up to 3.3 GPa at ambient temperature, corresponding to 3.0 GPa at low temperatures, without irreversible damage.

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Dilatometry under high pressure

Cited by 8 publications

References 3 publications

Multidimensional entropy landscape of quantum criticality

Multidimensional entropy landscape of quantum criticality

Probing the Mott physics inκ-(BEDT-TTF)₂X salts via thermal expansion

Three-wall piston-cylinder type pressure cell for muon-spin rotation/relaxation experiments

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Dilatometry under high pressure

Cited by 8 publications

References 3 publications

Multidimensional entropy landscape of quantum criticality

Multidimensional entropy landscape of quantum criticality

Probing the Mott physics inκ-(BEDT-TTF)2X salts via thermal expansion

Three-wall piston-cylinder type pressure cell for muon-spin rotation/relaxation experiments

Contact Info

Product

Resources

About

Probing the Mott physics inκ-(BEDT-TTF)₂X salts via thermal expansion