Versatile and compact capacitive dilatometer

Schmiedeshoff, G. M.; Lounsbury, Amanda W.; Luna, D J; Tracy, S. J.; Schramm, Anika; Tozer, S. W.; Correa, V. F.; Hannahs, S. T.; Murphy, T. P.; Palm, E. C.; Lacerda, A.; Bud’ko, Sergey L.; Canfield, Paul C.; Smith, James L.; Lashley, J. C.; Cooley, J. C.

doi:10.1063/1.2403088

Cited by 103 publications

(67 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A detailed description of the dilatometer is presented elsewhere 11 . The samples were lightly polished so as to have parallel surfaces which are also approximately parallel to the different crystallographic axis directions.…”

mentioning

confidence: 99%

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

et al. 2011

Self Cite

View full text Add to dashboard Cite

We present temperature dependent resistivity and ac-calorimetry measurements of CeVSb3 under pressure up to 8 GPa in a Bridgman anvil cell modified to use a liquid medium and in a diamond anvil cell using argon as a pressure medium. An initial increase of the ferromagnetic transition temperature TC with pressures up to 4.5 GPa is observed, followed by decrease of TC on further increase of pressure and finally its disappearance, in agreement with the Doniach model. We infer a ferromagnetic quantum phase transition around 7 GPa under hydrostatic pressure conditions from the extrapolation to 0 K of TC and the maximum of the A coefficient from low temperature fits of the resistivity ρ(T ) = ρ0 + AT n . No superconductivity under pressure was observed down to 0.35 K for this compound. In addition, differences in the TC(P) behavior when a slight uniaxial component is present are noticed and are correlated to the choice of pressure medium.

show abstract

mentioning

confidence: 99%

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…We note that in the low-temperature phase, the crystal structure of our sample is found to be a five-layered martensite (termed 5R or 10M ): the unit cell is monoclinic with the parameters a=4.2Å, b=5.5Å, c=21Å, α=γ=90 • and β=91 • [15]. The linear coefficient of thermal expansion was measured in a three-terminal capacitive dilatometer [19] over the range of 100 K < T < 250 K. The specific heat was measured using a thermal-relaxation method [20]. The magnetic moment was measured using a vibrating-sample magnetometer on a Quantum Design Physical Properties Measurement System (PPMS).…”

mentioning

confidence: 99%

Combined Experimental and Theoretical Investigation of the Premartensitic Transition inNi2MnGa

et al. 2008

Self Cite

View full text Add to dashboard Cite

Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni2MnGa over the temperature range 100 K < T < 250 K. All measurements detect clear signatures of the premartensitic transition (TPM ∼ 247 K) and the martensitic transition (TM ∼ 196 K). Temperature-dependent UPS shows a dramatic depletion of states (pseudogap) at TPM located 0.3 eV below the Fermi energy. First-principles electronic structure calculations show that the peak observed at 0.3 eV in the UPS spectra for T > TPM is due to the Ni-d minority-spin electrons. Below TM this peak disappears, resulting in an enhanced density of states at energies around 0.8 eV. This enhancement reflects Ni-d and Mn-d electronic contributions to the majority-spin density of states and is accompanied by significant reconstruction of the Fermi surface. [5] as a system undergoing a martensitic transition (MT) in its ferromagnetic phase (T C ∼ 380 K) with little magnetic hysteresis. In the last decade research on these alloys has focused on the structural and magnetic characterization and on their shape-memory applications [6]. First-principles calculations [7,8] and measurements on shape-memory alloys [9,10,11,12] indicate the driving role of the electronic structure and its relation to the lattice dynamics.The lattice dynamics of Ni 2 MnGa has been investigated from ultrasonic measurements [13] and neutron diffraction experiments [14,15,16]. It was found that the transverse TA 2 phonon branch exhibits pronounced softening at 1/3 of the zone boundary on decreasing the temperature, and this softening was described as a Bain distortion in the context of the Wechler, Lieberman, and Read theory of martensite formation [17]. In similar structural shape-memory alloys InTl [9], AuZn [10] and NiAl [11], this softening is associated with nesting features of the Fermi surface [8]. Below a certain temperature, there is a freezing of the displacements associated with this soft phonon so that a micro-modulated phase forms, which is described as a periodic distortion of the parent cubic phase [14]. In Ni 2 MnGa, the premartensitic phase develops with little or no thermal hysteresis and is driven by a magnetoelastic coupling [18]. On further cooling, Ni 2 MnGa transforms to an approximately fivelayered quasi-tetragonal martensitic structure. The lowtemperature phase is incommensurate [14] with a period (0.43,0.43,0) and exhibits well-defined phasons best characterized as charge-density wave (CDW) excitations [16].In this paper we study the role of conduction electrons in the two-step MT in Ni 2 MnGa using photoemission spectroscopy and thermodynamic measurements. LEED and X-ray diffraction Laue measurements show the quality of our sample is appropriate for high-resolution photoemission spectroscopy. Ultraviolet photoemission (UPS) measurements show the opening of a pseudogap at 0.3 eV below the Fermi energy at the MT and provide further evidence that the Fer...

show abstract

“…Thermal expansion data were obtained using a capacitive dilatometer constructed of OFHC copper, mounted in a Quantum Design PPMS instrument. A detailed description of the dilatometer is presented elsewhere [22]. The samples were cut and lightly polished so as to have parallel surfaces approximately parallel to the a in-plane direction and parallel to the c-direction with the distances L between the surfaces ranging between approximately 0.3 − 3 mm.…”

mentioning

confidence: 99%

Anisotropic thermal expansion ofAEFe₂As₂(AE= Ba, Sr, Ca) single crystals

Bud’ko

Canfield

2010

Philosophical Magazine

View full text Add to dashboard Cite

We report anisotropic thermal expansion of the parent, AEFe 2 As 2 (AE = Ba, Sr, and Ca), compounds. Above the structural/antiferromagnetic phase transition anisotropy of the thermal expansion coefficients is observed, with the coefficient along the a-axis being significantly smaller than the coefficient for the c-axis. The high temperature (200 K ≤ T ≤ 300 K) coefficients themselves have similar values for the compounds studied. The sharp anomalies associated with the structural/antiferromagnetic phase transitions are clearly seen in the thermal expansion measurements. For all three pure compounds the "average" a-value increases and the c-lattice parameter decreases on warming through the transition with the smallest change in the lattice parameters observed for SrFe 2 As 2 . The data are in general agreement with the literature data from X-ray and neutron diffraction experiments.Keywords: iron-arsenides; thermal expansion; anisotropy; structural phase transition;For over a year many experimental and theoretical aspects of physics of ternary AETM 2 As 2 (AE = Ba, Sr, and Ca; TM = transition metal) compounds were studied in great detail. One of the motivations for such studies was a desire to shed some light on what are the salient parameters that govern doping-or pressureinduced superconductivity [1,2,3,4,5,6,7] in these materials. The common feature of the parent compounds [8,9,10,11,12,13,14] is a distinct, moderately high temperature (above ∼ 100 K), coupled, structural/antiferromagnetic phase transition that generally is argued to be of the first order. Thermal expansion is often claimed to be uniquely sensitive to just such magnetic, structural and superconducting transitions [15]. For example, in Co-doped BaFe 2 As 2 , anisotropic thermal expansion measurements [16,17,18] have been instrumental in inferring unusually large, anisotropic, uniaxial pressure derivatives of superconducting transition temperature. For the parent AETM 2 As 2 materials though, we are aware only of data from pure BeFe 2 As 2 [16]. In this work we present and compare anisotropic thermal expansion measurements for three parent compounds, AEFe 2 As 2 (AE = Ba, Sr, and Ca). (Data for BaFe 2 As 2 are taken from [16].) For completeness, data on Sn -grown BeFe 2 As 2 [19] are included as well.Single crystals of AEFe 2 As 2 (AE = Ba, Sr, and Ca) were grown using conventional high temperature solution growth technique [20]. Details of growth conditions and physical properties of these samples are outlined in [10,13,19,21]. It should be noted, though, that BaFe 2 As 2 samples grown out of FeAs as well as Sn have been examined. The SrFe 2 As 2 and CaFe 2 As 2 samples were both grown out of Sn. The BaFe 2 As 2 /FeAs, SrFe 2 As 2 /Sn and CaFe 2 As 2 /Sn samples are considered to be pure and well ordered whereas BaFe 2 As 2 /Sn is known to

show abstract

Versatile and compact capacitive dilatometer

Cited by 103 publications

References 21 publications

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

Combined Experimental and Theoretical Investigation of the Premartensitic Transition inNi2MnGa

Anisotropic thermal expansion ofAEFe₂As₂(AE= Ba, Sr, Ca) single crystals

Contact Info

Product

Resources

About

Versatile and compact capacitive dilatometer

Cited by 103 publications

References 21 publications

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

Phase diagram of CeVSb3under pressure and its dependence on pressure conditions

Combined Experimental and Theoretical Investigation of the Premartensitic Transition inNi2MnGa

Anisotropic thermal expansion ofAEFe2As2(AE= Ba, Sr, Ca) single crystals

Contact Info

Product

Resources

About

Anisotropic thermal expansion ofAEFe₂As₂(AE= Ba, Sr, Ca) single crystals