Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-$T_{c}$ Superconductors

TL;DR

This study uses muon spin relaxation measurements to investigate magnetic-field-induced effects in various high-$T_c$ superconductors, revealing strong quasi-static magnetism above $T_c$ in underdoped and Eu-doped samples, but not in overdoped or optimally doped ones.

Contribution

It demonstrates the presence of field-induced quasi-static magnetism in underdoped and Eu-doped cuprates above their critical temperatures, highlighting doping-dependent magnetic phenomena.

Findings

Field-induced magnetism exists above $T_c$ in underdoped and Eu-doped samples.

No such magnetism is observed in overdoped or optimally doped samples.

Magnetic susceptibility diverges near 25 K in certain compounds.

Abstract

Muon spin relaxation ($\mu$SR) measurements in high transverse magnetic fields ($\parallel \hat c$) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped (La,Sr)$_{2}$CuO$_{4}$ and La$_{1.875}$Ba$_{0.125}$CuO$_{4}$, existing well above $T_{c}$ and $T_{N}$. The susceptibility-counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards $T \sim 25$ K. No field-induced magnetism was detected in overdoped La$_{1.81}$Sr$_{0.19}$CuO$_{4}$, optimally doped Bi2212, and Zn-doped YBa$_{2}$Cu$_{3}$O$_{7}$.