Grain Boundary Induced Magneto-Far Infrared Resonances in Superconducting YBa$_2$Cu$_3$O$_{7-\delta }$ Thin Films

TL;DR

This study observes specific magneto-infrared spectral features in YBa₂Cu₃O₇−δ thin films caused by grain boundaries, attributing them to vortex core excitations, and models them with Lorentzian oscillators.

Contribution

It reports the detection of magneto-infrared resonances linked to grain boundary misorientation in YBa₂Cu₃O₇−δ films, proposing vortex core excitations as their origin.

Findings

Spectral features at 80, 116, and 160 cm⁻¹ observed.

Features well modeled by Lorentzian oscillators.

Resonances attributed to vortex core excitations.

Abstract

Spectral features induced by 45$^{\circ }$ in-plane misoriented grains have been observed in the far infrared magneto-transmission of YBa$_2$Cu$_3$O$% _{7-\delta }$ thin films. Two strong dispersive features are found at 80 and 160 $cm^{-1}$ and a weaker one at 116 $cm^{-1}$. The data can be well represented by Lorentzian oscillator contributions to the conductivity. Several possible interpretations are discussed. We conclude that the resonances are due to vortex core excitations.