Magnetic Phase Diagram of Li_2(Pd_{1-x}Pt_x)_3B by AC Susceptometry

TL;DR

This study maps the magnetic phase diagram and superconducting parameters of Li_2(Pd_{1-x}Pt_x)_3B across different platinum concentrations, revealing that the phase diagram remains stable despite changes in pairing and band structure.

Contribution

It provides the first detailed H-T phase diagram for Li_2(Pd_{1-x}Pt_x)_3B and discusses the impact of cation substitution on superconducting properties.

Findings

Coherence length may vary linearly with platinum concentration

H-T phase diagram remains essentially unchanged despite fundamental changes in pairing state

Upper critical field H_c2(0) is not anomalously high across Pt content

Abstract

The H-T phase diagram and several superconducting parameters for Li_2(Pd_{1-x}Pt_x)_3B have been determined as a function of cation substitution x. Notably, the coherence length may be linear in platinum concentration. Despite the superconducting pairing state and band structure apparently changing fundamentally, the H-T phase diagram is essentially unchanged. Unusual aspects of the shape of the H-T phase diagram are discussed. The upper critical field H_c2(0) is not anomalously high for any Pt content, likely due to an absence of high carrier masses - in such a case, the value of H_c2(0) would not serve as a probe for novel physics.