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arXiv · 1402.4961

Investigations of the superconducting states of noncentrosymmetric LaPdSi3 and LaPtSi3

M. Smidman·A. D. Hillier·D. T. Adroja·M. R. Lees·V. K. Anand·R. P. Singh·R. I. Smith·D. M. Paul·G. Balakrishnan
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Abstract

The noncentrosymmetric superconductors LaPdSi3 and LaPtSi3 have been studied with magnetization, specific heat, resistivity and muon spin rotation/relaxation (muSR) measurements. These crystallize in the tetragonal BaNiSn3 structure and superconductivity is observed at Tc = 2.65 K for LaPdSi3 and Tc = 1.52(6) K for LaPtSi3. The results are consistent with both compounds being weakly coupled, fully gapped superconductors but muSR measurements reveal that LaPdSi3 is a bulk type-I superconductor while LaPtSi3 is a type-II material with a Ginzburg-Landau parameter of kappa = 2.49(4). This is further supported by specific heat measurements, where the transition in an applied field is first-order in LaPdSi3 but second-order in LaPtSi3. The electronic specific heat in the superconducting state was analyzed using an isotropic s-wave model that gave Delta/kTc = 1.757(4) for LaPdSi3 and 1.735(5) for LaPtSi3. The temperature dependence of the effective penetration depth of LaPtSi3 was extracted from muSR measurements and was fitted giving Delta/kTc = 1.60(8) and lambda(0) = 239(3) nm. A critical field of Bc(0) = 182.7 G was obtained for LaPdSi3 from muSR measurements, which is in good agreement with the calculated thermodynamic critical field.

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M. Smidman, A. D. Hillier, D. T. Adroja, M. R. Lees, V. K. Anand, R. P. Singh, R. I. Smith, D. M. Paul, G. Balakrishnan. 2014-02-20. Investigations of the superconducting states of noncentrosymmetric LaPdSi3 and LaPtSi3. https://doi.org/10.1103/physrevb.89.094509

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