Effects of annealing temperature and time on the electrical resistivity of single crystal RNi2B2C (R=Gd–Lu, Y)

Miao, Xiaochang; Bud’ko, Sergey L.; Canfield, Paul C.

doi:10.1016/s0925-8388(02)00176-7

Cited by 24 publications

(31 citation statements)

References 17 publications

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“…Sputtered Au contacts allowed us to apply currents along the ab-planes while measuring the voltage across the sample. We observed a slight reduction of T c (∼ 0.5 K) due to sample preparation, which is consistent with the previously reported increase in T c after annealing [31]. The small decrease in T c does not affect the overall results of the present study; it left both T N and the shape of H c2 (T ) unchanged.…”

supporting

confidence: 92%

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Weigand

Civale²,

Baca³

et al. 2013

Phys. Rev. B

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We report on transport and magnetization measurements of the critical current density Jc in ErNi2B2C single crystals that show strongly enhanced vortex pinning at the Néel temperature TN and low applied fields. The height of the observed Jc peak decreases with increasing magnetic field in clear contrast with that of the peak effect found at the upper critical field. We also performed the first angular transport measurements of Jc ever conducted on this compound. They reveal the correlated nature of this pinning enhancement, which we attribute to the formation of antiphase boundaries at TN . 74.25.Sv, 74.25.Wx, 74.70.Dd Single quanta of magnetic flux enter a type II superconductor in the form of vortices when it is exposed to a magnetic field H. This is a big setback for applications, because when an electrical current J is applied, vortices move and energy is dissipated. This movement can be arrested by non-superconducting defects that pin vortices by lowering the system energy. The interaction between vortices and pinning centers has been studied extensively for decades, focused mainly on the so-called vortex core pinning (caused by the local suppression of the superconducting order parameter) [1,2]. Less explored is the interplay between vortices and magnetic media, which could offer pinning forces superior to those from core pinning [3][4][5][6]. A common difficulty of studying magnetic pinning is the inability of separating the magnetic and core contributions. It is, therefore, of great advantage to study systems where the magnetic transition takes place inside the superconducting phase, allowing one to compare the behavior with and without the magnetically ordered phase.There are a considerable number of materials in which to study the coexistence between superconductivity and ordered magnetic phases, such as the Chevrel-phases [7], CeCoIn 5 [8], and recently iron pnictides [9][10][11]. However, the rare earth-nickel-borocarbide family (RENi 2 B 2 C, where RE is a rare earth element) [12][13][14] has several advantages, namely a relatively high superconducting transition temperature T c and the tunability of the ratio between its magnetic and superconducting ordering temperatures, which can be changed by using different rare earth elements [15,16]. The readily available high-purity single crystals allow one to study the effects of magnetic pinning without any significant defect (non-magnetic) contribution [15].Among the borocarbide family the compound with RE = Er has a T c of 10.5 K and a Néel temperature T N of 6.0 K [17]. The occurrence of antiferromagnetism directly influences the superconducting properties, as seen in the upper critical field vs temperature curve, where H c2 (T ) is slightly suppressed just below T = T N for H c and has an inflection point for H ab [17]. This is a consequence of the local moments ordering in the antiferromagnetic phase, as was shown experimentally [17,18] and theoretically [19,20].In addition to the occurrence of antiferromagnetism, at T = T N a tetragonal to ortho...

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supporting

confidence: 92%

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Weigand

Civale²,

Baca³

et al. 2013

Phys. Rev. B

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“…An as-grown bar was oriented with a Laue camera and cut into a close to prismoidal shape with two pairs of parallel surfaces, so that TE and MS were measured along [110] (L = 3.03 mm) and [001] (L = 1.82 mm) directions. After shaping, both samples were annealed in dynamic vacuum (10 −5 − 10 −6 Torr) at 950 • C [13]. It should be mentioned that for reasons unrelated to the objectives of this work, the sample A was grown with isotopically pure 10 B and the sample B with 11 B. Magnetization measurements were performed using a commercial MPMS-5 (Quantum Design, Inc.) SQUID magnetometer; ac resistance (f = 16 Hz, I = 3 mA) and heat capacity were measured with ACT and heat capacity options of a PPMS-9 instrument (Quantum Design, Inc.).…”

Section: Experimental Methodsmentioning

confidence: 99%

Anisotropic thermal expansion and magnetostriction of YNi₂B₂C single crystals

Bud’ko

Schmiedeshoff

Lapertot

et al. 2006

J. Phys.: Condens. Matter

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Abstract. We present results of anisotropic thermal expansion and low temperature magnetostriction measurements on YNi 2 B 2 C single crystals grown by high temperature flux and floating zone techniques. Quantum oscillations of magnetostriction were observed at low temperatures for H c starting at fields significantly below H c2 (H < 0.7H c2 ). Large irreversible, longitudinal magnetostriction was seen in both, inplane and along the c-axis, directions of the applied magnetic field in the intermediate superconducting state. Anisotropic uniaxial pressure dependencies of T c were evaluated using results of zero field, thermal expansion measurements.

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“…• C for ∼ 100 hours [19]. Thermal expansion and magnetostriction were measured using a capacitive dilatometer constructed of OFHC copper; a detailed description of the dilatometer will appear elsewhere [20].…”

mentioning

confidence: 99%

Anisotropic thermal expansion and evaluation of uniaxial pressure dependence of superconducting and magnetic transitions in ErNi2B2C

Bud’ko¹,

Schmiedeshoff²,

Canfield³

2006

Solid State Communications

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We present anisotropic thermal expansion measurements on single crystalline ErNi 2 B 2 C. All three, superconducting, antiferromagnetic and weak ferromagnetic phase transitions are unambiguously distinguished in the data. Anisotropic uniaxial pressure dependencies of the transitions are estimated based on the Ehrenfest relation, leading to a conclusion, in particular, that weak ferromagnetic state will be suppressed by small, order of several kbar, hydrostatic pressure.Key words: A. magnetically ordered materials, A. superconductors, D. thermal expansion PACS: 65.40. De, 74.70.Dd, 75.30.Kz, 75.40.Cx, 75.80.+q Quaternary borocarbides, in particular the members of the RNi 2 B 2 C (R = Gd-Lu, Y) series of compounds, exhibit a plethora of complex phenomena: co-existence of local moment magnetism and superconductivity, non-locality and flux line lattice transitions, heavy fermion physics and intricate metamagnetism [1,2,3,4]. ErNi 2 B 2 C superconducts below ∼ 10 K [5,6], below T N ≈ 6 K superconductivity coexists with an incommensurate antiferromagnetic state with the ordering wave vector q ≈ 0.55 a * [8,9,7], and then, on further cooling, a weak ferromagnetic component develops below T W F M ≈ 2.3 K [10,11,12].Despite a large number of publications on physical properties of ErNi 2 B 2 C, few of them address temperature dependent structural changes in the material. The evolution of the lattice parameters between 360 K and 90 K, as measured by single crystal X-ray diffraction, was reported in Ref. [13]. A magnetoelastic tetragonal-to-orthorhombic structural distortion was observed [14] below T N by synchrotron X-ray scattering. A λ-type anomaly in thermal expansion at In this publication we report high resolution, anisotropic (c-axis and a-axis) thermal expansion (TE) and longitudinal, low temperature, magnetostriction (MS) measurements for H a on single crystalline ErNi 2 B 2 C. These measurements were performed with the intent to study the anomalies in TE associated with all three salient transition temperatures (to the best of our knowledge, for two of them, T c and T W F M , no TE anomalies were reported so far) and to evaluate the uniaxial pressure derivatives of the three transition temperatures using the the thermodynamic Ehrenfest relation.Plate-like single crystals of ErNi 2 B 2 C with the c-axis perpendicular to the plates were grown by a Ni 2 B high temperature flux method (see Refs. [1,7,17,18] for more details). For the TE/MS measurements the ErNi 2 B 2 C crystal was shaped into a nearly rectangular bar, with two pairs of parallel surfaces, so that the measurements were performed along [100] (L = 2.23 mm) and [001] (L = 1.42 mm) directions. After shaping, the sample was annealed in dynamic vacuum (10 −5 − 10 −6 Torr) at 950• C for ∼ 100 hours [19]. Thermal expansion and magnetostriction were measured using a capacitive dilatometer constructed of OFHC copper; a detailed description of the dilatometer will appear elsewhere [20]. The dilatometer was mounted in a Quantum Design PPMS-14 instrumen...

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Effects of annealing temperature and time on the electrical resistivity of single crystal RNi2B2C (R=Gd–Lu, Y)

Cited by 24 publications

References 17 publications

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Anisotropic thermal expansion and magnetostriction of YNi₂B₂C single crystals

Anisotropic thermal expansion and evaluation of uniaxial pressure dependence of superconducting and magnetic transitions in ErNi2B2C

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Effects of annealing temperature and time on the electrical resistivity of single crystal RNi2B2C (R=Gd–Lu, Y)

Cited by 24 publications

References 17 publications

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Strong enhancement of the critical current at the antiferromagnetic transition in ErNi2B2C single crystals

Anisotropic thermal expansion and magnetostriction of YNi2B2C single crystals

Anisotropic thermal expansion and evaluation of uniaxial pressure dependence of superconducting and magnetic transitions in ErNi2B2C

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Anisotropic thermal expansion and magnetostriction of YNi₂B₂C single crystals