The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
H. Sato - One of the best experts on this subject based on the ideXlab platform.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros4sb12
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs 4 Sb 12 in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ( F P ). Estimated F P at the peak exhibits apparent dependence on applied field direction composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity (κ). The result is discussed in correlation with the double-step superconducting (SC) transition in specific heat and the multiple SC-phases inferred from the angular dependence of κ.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros _ 4 sb _ 12
arXiv: Strongly Correlated Electrons, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Novel features in the flux-Flow Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Flux-Flow Resistivity in the heavy fermion superconductor PrOs4Sb12
Journal of Magnetism and Magnetic Materials, 2004Co-Authors: Miki Kobayashi, Hitoshi Sugawara, S. R. Saha, Takahiro Namiki, H Fujiwara, Yuji Aoki, H. SatoAbstract:Abstract We have measured the field dependence of electrical Resistivity in the mixed state of the heavy fermion superconductor PrOs 4 Sb 12 . We have found a double peak anomaly in the flux-Flow Resistivity corresponding to the multiple superconducting phases determined by the thermal conductivity measurements.
Yuji Aoki - One of the best experts on this subject based on the ideXlab platform.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros4sb12
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs 4 Sb 12 in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ( F P ). Estimated F P at the peak exhibits apparent dependence on applied field direction composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity (κ). The result is discussed in correlation with the double-step superconducting (SC) transition in specific heat and the multiple SC-phases inferred from the angular dependence of κ.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros _ 4 sb _ 12
arXiv: Strongly Correlated Electrons, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Novel features in the flux-Flow Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Flux-Flow Resistivity in the heavy fermion superconductor PrOs4Sb12
Journal of Magnetism and Magnetic Materials, 2004Co-Authors: Miki Kobayashi, Hitoshi Sugawara, S. R. Saha, Takahiro Namiki, H Fujiwara, Yuji Aoki, H. SatoAbstract:Abstract We have measured the field dependence of electrical Resistivity in the mixed state of the heavy fermion superconductor PrOs 4 Sb 12 . We have found a double peak anomaly in the flux-Flow Resistivity corresponding to the multiple superconducting phases determined by the thermal conductivity measurements.
Miki Kobayashi - One of the best experts on this subject based on the ideXlab platform.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros4sb12
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs 4 Sb 12 in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ( F P ). Estimated F P at the peak exhibits apparent dependence on applied field direction composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity (κ). The result is discussed in correlation with the double-step superconducting (SC) transition in specific heat and the multiple SC-phases inferred from the angular dependence of κ.
-
novel features in the flux Flow Resistivity of the heavy fermion superconductor pros _ 4 sb _ 12
arXiv: Strongly Correlated Electrons, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Novel features in the flux-Flow Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$
Journal of the Physical Society of Japan, 2005Co-Authors: Miki Kobayashi, Hitoshi Sugawara, H Fujiwara, H. Sato, Yuji AokiAbstract:We have investigated the electrical Resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-Flow Resistivity as a function of magnetic field below the upper critical field for the first time, indicating double peaks in the pinning force density ($F_{\rm P}$). Estimated $F_{\rm P}$ at the peak exhibits apparent dependence on applied field direction; composed of two-fold and four-fold symmetries mimicking the reported angular dependence of thermal conductivity ($\kappa$). The result is discussed in correlation with the double step superconducting (SC) transition in the specific heat and the multiple SC-phases inferred from the angular dependence of $\kappa$.
-
Flux-Flow Resistivity in the heavy fermion superconductor PrOs4Sb12
Journal of Magnetism and Magnetic Materials, 2004Co-Authors: Miki Kobayashi, Hitoshi Sugawara, S. R. Saha, Takahiro Namiki, H Fujiwara, Yuji Aoki, H. SatoAbstract:Abstract We have measured the field dependence of electrical Resistivity in the mixed state of the heavy fermion superconductor PrOs 4 Sb 12 . We have found a double peak anomaly in the flux-Flow Resistivity corresponding to the multiple superconducting phases determined by the thermal conductivity measurements.
Atsutaka Maeda - One of the best experts on this subject based on the ideXlab platform.
-
exceptional suppression of flux Flow Resistivity in fese 0 4 te 0 6 by back Flow from excess fe atoms and se te substitutions
Physical Review B, 2015Co-Authors: Tatsunori Okada, Yoshinori Imai, Hideyuki Takahashi, Fuyuki Nabeshima, Atsutaka MaedaAbstract:We measured the microwave surface impedance of FeSe$_{0.4}$Te$_{0.6}$ single crystals with- and without external magnetic fields. The superfluid density exhibited a quadratic temperature dependence, indicating a strong pair-breaking effect. The flux-Flow Resistivity behaved as $\rho_f(B\ll B_{\rm c2})/\rho_n=\alpha B/B_{\rm c2}$. The observed $\alpha$ value of $\approx0.66$ was considerably smaller than that of other Fe-based materials ($\alpha\geq1$) and was attributed to a back-Flow of superfluids remarkable in disordered superconductors. This is the first-time observation of the back-Flow phenomenon caused by an origin other than the vortex pinning in multiple-band systems.
-
penetration depth and flux Flow Resistivity measurements of bafe2 as0 55p0 45 2 single crystals
Physica C-superconductivity and Its Applications, 2014Co-Authors: Tatsunori Okada, Yoshinori Imai, Hideyuki Takahashi, Masamichi Nakajima, A Iyo, H Eisaki, Atsutaka MaedaAbstract:Abstract We measured the surface impedance of BaFe 2 (As 0.55 P 0.45 ) 2 single crystals under finite magnetic fields by using a microwave technique. We found that the penetration depth increased as λ ( T ) = λ ( 0 ) + A × T n with an exponent of n ≈ 1.7 in the temperature region of 0.1 T / T c 0.2 . The observed fractional exponent can be understood by considering that this material has gaps with lines of nodes and nodeless gaps with large anisotropy. The flux-Flow Resistivity showed an almost H -linear dependence and a remarkably rapid enhancement in the low- H region; ρ f / ρ n ≈ α H / H c 2 with a gradient of α > 2.5 . Such a behavior is similar to that of SrFe 2 (As,P) 2 . By comparing these with results of 111-materials and SrFe 2 (As 0.7 P 0.3 ) 2 , it has been clarified that the gap anisotropy dominates the gradient α of iron-based materials.
-
Magnetic penetration depth and flux-Flow Resistivity measurements on NaFe0.97Co0.03As single crystals
Physica C: Superconductivity, 2013Co-Authors: Tatsunori Okada, H. Takahashi, Yoshinori Imai, Kentaro Kitagawa, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Atsutaka MaedaAbstract:Abstract We measured the surface impedance of NaFe 1− x Co x As ( x ≈ 0.03, optimally doped) single crystals under finite magnetic fields. At low temperatures ( T T c ), the penetration depth of these crystals was increased as λ ( T ) − λ (0) = A × T n with an exponent n ≈ 2, indicating the realization of the gapless superconductivity. The flux-Flow Resistivity, ρ f , behaved similarly to the Bardeen–Stephen prediction, ρ f / ρ n = B / B c 2 . However, the electronic state inside the vortex core was not so dirty. By comparing the results with those of LiFeAs 1− x P x and SrFe 2 (As 0.7 P 0.3 ) 2 , it has been clarified that the gap anisotropy dominates the gradient of ρ f ( B ).
-
investigation of the superconducting gap structure in srfe 2 as 0 7 p 0 3 2 by magnetic penetration depth and flux Flow Resistivity analysis
Physical Review B, 2012Co-Authors: Hideyuki Takahashi, Tatsunori Okada, Yoshinori Imai, Kentaro Kitagawa, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Atsutaka MaedaAbstract:We measured the microwave surface impedances and obtained the superfluid density and flux Flow Resistivity in single crystals of a phosphor-doped iron-based superconductor SrFe${}_{2}$(As${}_{1\ensuremath{-}x}$P${}_{x}$)${}_{2}$ single crystals ($x=0.30$, ${T}_{c}=25\phantom{\rule{4pt}{0ex}}\mathrm{K}$). At low temperatures, the superfluid density, ${n}_{s}(T)/{n}_{s}(0)$, obeys a power law, ${n}_{s}(T)/{n}_{s}(0)=1\ensuremath{-}C{(T/{T}_{c})}^{n}$, with a fractional exponent of $n=1.5$--1.6. The flux Flow Resistivity was significantly enhanced at low magnetic fields. These features are consistent with the presence of line nodes on at least one band and modulated nodeless gap with deep minimum on the same bands and/or other bands. The remarkable difference observed in the superconducting gap structure between SrFe${}_{2}$(As${}_{1\ensuremath{-}x}$P${}_{x}$)${}_{2}$ and BaFe${}_{2}$(As${}_{1\ensuremath{-}x}$P${}_{x}$)${}_{2}$ in our experiments is important for clarifying the mechanism of iron-based superconductivity in the 122 system.
-
Quasiparticle Electronic Structure of a New Surperconductor, Y2C3, in the Mixed State Investigated by Specific Heat and Flux-Flow Resistivity
Journal of the Physical Society of Japan, 2008Co-Authors: Satoshi Akutagawa, Jun Goryo, Hiroshi Matsukawa, Atsutaka Maeda, Haruhisa Kitano, Takeyoshi Ohashi, Jun AkimitsuAbstract:In this paper, we investigate the electronic structure of quasiparticle in the vortex state of Y 2 C 3 by the measurements of the specific heat, C , and the flux-Flow Resistivity, ρ f . In contrast to a conventional s -wave superconductor, C / T and ρ f showed nonlinear B dependences at low temperatures. The result is discussed in terms of the two gap superconductivity. We estimated the viscosity and the mean free path of the quasiparticles in the vortex core for Y 2 C 3 . While we found that Y 2 C 3 is a clean superconductor in a previous study, the mean free path of the quasiparticles in the vortex core was limited to the coherence length because of the Andreev reflection at the vortex–core boundary in this study.
C C Almasan - One of the best experts on this subject based on the ideXlab platform.
-
relationship between critical current and flux Flow Resistivity in the mixed state of ba fe 1 x co x 2 as 2
Physical Review B, 2017Co-Authors: X Y Huang, Yogesh Singh, D J Haney, H Xiao, Haihu Wen, S Zhang, M Dzero, C C AlmasanAbstract:We studied the temperature and magnetic field dependence of vortex dissipation and critical current in the mixed-state of unconventional superconducting alloys Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ ($0.044 \leq x \leq 0.100$) through current-voltage measurements. Our results reveal that all the electric field $E$ vs current density $j$ curves in the Ohmic regime merge to one point ($j_0,E_0$) and that there is a simple relationship between the critical current density $j_c$ and flux-Flow Resistivity $\rho_{\rm ff}$: $\rho_{\rm ff}/\rho_{\rm n} = (1- j_{c}/j_{0})^{-1}$, where $\rho_{\rm n}=E_0/j_0$ is the normal-state Resistivity just above the superconducting transition. In addition, $E_0$ is positive for all five dopings, reflecting the abnormal behavior of the flux-Flow Resistivity $\rho_{\rm ff}$: it increases with decreasing magnetic field. In contrast, $E_0$ is negative for the conventional superconductor Nb since, as expected, $\rho_{\rm ff}$ decreases with decreasing magnetic field. Furthermore, in the under-doped and over-doped single crystals of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, the parameter $E_0$ remains temperature independent, while it decreases with increasing temperature for the single crystals around optimal doping ($ 0.060\leq x\leq 0.072 $). This result points to the co-existence of superconductivity with some other phase around optimal doping.
-
universality and unconventional enhancement of flux Flow Resistivity in ba fe _ 1 x co _x _2 as _2
Physical Review B, 2017Co-Authors: X Y Huang, D J Haney, H Xiao, Haihu Wen, M Dzero, Y P Singh, C C AlmasanAbstract:Measurements of the current-voltage characteristics ($I\ensuremath{-}V$) were performed on ${\mathrm{Ba}(\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}{)}_{2}{\mathrm{As}}_{2}$ single crystals with doping level $0.044\ensuremath{\le}x\ensuremath{\le}0.100$. An unconventional increase in the flux-Flow Resistivity ${\ensuremath{\rho}}_{\mathrm{ff}}$ with decreasing magnetic field $H$ was observed across this doping range. Such an abnormal field dependence of ${\ensuremath{\rho}}_{\mathrm{ff}}$ is in contrast with the linear ${\ensuremath{\rho}}_{\mathrm{ff}}(H)$ of conventional type-II superconductors, but similar to the behavior recently observed in the heavy-fermion superconductor ${\mathrm{CeCoIn}}_{5}$. A significantly enhanced ${\ensuremath{\rho}}_{\mathrm{ff}}$ was found for the $x=0.06$ single crystals, implying a strong single-particle energy dissipation around the vortex cores. At different temperatures and fields and for a given doping concentration, the normalized ${\ensuremath{\rho}}_{\mathrm{ff}}$ scales with normalized field and temperature. The doping level dependence of the scaling parameters strongly suggests that the abnormal upturn in ${\ensuremath{\rho}}_{\mathrm{ff}}$ is likely related to the enhancement of spin fluctuations around the vortex cores of the samples with $x\ensuremath{\approx}0.06$.