μSR and magnetometry study of the type-I superconductor BeAu

Abstract

We present muon spin rotation and relaxation (µSR) measurements as well as demagnetising field corrected magnetisation measurements on polycrystalline samples of the noncentrosymmetric superconductor BeAu. From µSR measurements in a transverse field, we determine that BeAu is a type-I superconductor with Hc = 256 Oe, amending the previous understanding of the compound as a type-II superconductor. To account for demagnetising effects in magnetisation measurements, we produce an ellipsoidal sample, for which a demagnetisation factor can be calculated. After correcting for demagnetising effects, our magnetisation results are in agreement with our µSR measurements. Using both types of measurements we construct a phase diagram from T = 30 mK to Tc ≈ 3.25 K. We then study the effect of hydrostatic pressure and find that 450 MPa decreases Tc by 34 mK, comparable to the change seen in type-I elemental superconductors Sn, In and Ta, suggesting BeAu is far from a quantum critical point accessible by the application of pressure. arXiv:1902.00073v1 [cond-mat.supr-con]

Y4Be33Pt16 – a non-centrosymmetric cage superconductor with multi-centre bonding in the framework

“…27,28 However, a more comprehensive analysis of the superconducting state in Y 4 Be 33 Pt 16 is currently underway. In particular, because several in-depth muon spin-rotation, relaxation, and resonance experiments performed on another Be-containing non-centrosymmetric superconductor BeAu 24 revealed that not only type-I character, 29 but also a multi-gap nature of superconductivity 30 may exist in such unconventional systems.…”

Single-gap versus two-gap scenario: Specific heat and thermodynamic critical field of the noncentrosymmetric superconductor BeAu

“…[47,50], respectively. Note that currently, three sets of C e (T ) and B c (T ) data for BeAu are available in the literature [46][47][48][49][50][51]. Among them, the C e (T ) and B c (T ) dependences from Refs.…”

Isotropic single gap superconductivity of elemental Pb: the `smiling' approach

“…The magnetic field distribution in a type-I superconductor in the intermediate state, which is probed directly by means of TF-µSR, consists of two sharp peaks corresponding to the response of the domains remaining in the Meissner state (B = 0) and in the normal state (B ≡ B c > B ex ). Consequently, the value of B c could be directly and very precisely determined by measuring the position of the B > B ex peak [18,22,[26][27][28][29][30][31][32][35][36][37][38][39][40]. The details of the TF-µSR experiments on elemental Pb and the data analysis procedure are discussed in the Supplemental Material [41].…”