A. T. Savici — Page 3

arXiv2003

Magnetism and superconductivity in CeRh_{1-x}Ir_xIn_5 heavy fermion materials

We report on zero-field muon spin relaxation studies of cerium based heavy-fermion materials CeRh_{1-x}Ir_xIn_5. In the superconducting x=0.75 and 1 compositions muon spin relaxation functions were found to be temperature independent across T_c; no evidence for the presence of electronic magnetic moments was observed. The x=0.5 material is antiferromagnetic below T_N=3.75 K and superconducting below T_c=0.8 K. Muon spin realxation spectra show the gradual onset of damped coherent oscillations characteristic of magnetic order below T_N. At 1.65 K the total oscillating amplitude accounts for at least 85% of the sample volume. No change in muon precession frequency or amplitude is detected on cooling below T_c, indicating the microscopic coexistence of magnetism and superconductivity in this material.

cond-mat.supr-con↗

arXiv2002

Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4 La$_{2}$CuO$_{4.11}$ and La$_{1.88}$Sr$_{0.12}$CuO$_{4}$

This paper reports muon spin relaxation (MuSR) measurements of two single crystals of the title high-Tc cuprate systems where static incommensurate magnetism and superconductivity coexist. By zero-field MuSR measurements and subsequent analyses with simulations, we show that (1) the maximum ordered Cu moment size (0.36 Bohr magneton) and local spin structure are identical to those in prototypical stripe spin systems with the 1/8 hole concentration; (2) the static magnetism is confined to less than a half of the volume of the sample, and (3) regions with static magnetism form nano-scale islands with the size comparable to the in-plane superconducting coherence length. By transverse-field MuSR measurements, we show that Tc of these systems is related to the superfluid density, in the same way as observed in cuprate systems without static magnetism. We discuss a heuristic model involving percolation of these nanoscale islands with static magnetism as a possible picture to reconcile heterogeneity found by the present MuSR study and long-range spin correlations found by neutron scattering.

cond-mat.supr-con↗