Normal state resistivity, upper critical field, and Hall effect in superconducting perovskiteMgCNi3

Abstract

The normal state resistivtity, upper critical field H c2 and Hall coefficientAbove 70 K, ρ(T ) fits well curve predicted by Bloch-Grüneisen theory consistently with electron-phonon scattering. H c2 (0) was estimated to be about 15.0 Tesla within the weak-coupling BCS theory, and the superconducting coherence length ξ(0) is approximately 47Å. R H of M gCN i 3 is negative for the whole temperature range which definitely indicates that the carrier in M gCN i 3 is electron-type. R H is temperature independent between T c and ∼ 140 K. Above ∼ 140 K, the magnitude of R H decreases as temperature rises. At T = 100 K, the carrier density is 1.0 × 10 22 /cm 3 , which is comparable with that in perovskite (Ba, K)BiO 3 , and less than that of the metallic binary M gB 2 .

Experimental determination of superconducting parameters for the intermetallic perovskite superconductorMgCNi3

“…This value is in good agreement with a earlier report of (0)ϭ47 Å. 12 The (0) estimated from H c2 (0) is actually the GL coherence length GL (0), which is comparable to Pippard coherence length p . Both GL (0) and p depend on the mean-free-path l of electrons.…”

“…12 where carrier density n and residual resistivity 0 were measured on the identical sample. Since the estimated l is very short, MgCNi 3 is probably a bad metal, like SrRuO 3…”

Electronic, vibrational, superconducting and thermodynamic properties of cubic antiperovskite ZnNNi3

“…Following this experimental work [1], several experimental attempts [2][3][4][5][6][7][8][9][10] have been made to determine superconducting parameters of this intermetallic perovskite superconductor. These experimental measurements indicate that MgCNi 3 is an s-wave BCS superconductor.…”

Suppression of superconductivity in Mn-substitutedMgCNi3

“…However the strength of electron-phonon coupling reported varies from weak [13], moderate [14] to strong coupling [15,16]. NMR studies indicate that the nature of pairing to be s-wave [17], and Hall effect results show that the carriers are of electron type [13]. However, tunnelling experiments indicate that MgCNi 3 is a strong coupling superconductor with non s-wave pairing symmetry [15].…”