Microwave Analysis of Unconventional Superconductors with Coplanar-Resonator Techniques (PoliTO Springer Series)

This book provides a thorough overview of methods and approaches to the experimental characterization of superconductors at microwave frequencies, and includes a detailed description of the two main techniques, both based on the use of coplanar waveguide resonators, that the authors employed to investigate the properties of unconventional superconductors. In the second part several case studies are described, covering a large spectrum of materials and issues. Particular emphasis is given to recent hot topics concerning iron-based superconductors, both of fundamental nature and relevant for applications. The book is intended as a learning tool for researchers in the field, and serves as a guide providing inspiring examples of the use of coplanar resonator techniques to address key topics in the field of unconventional superconductivity. Preface Contents Acronyms and Symbols Part I Methods 1 Resonant Methods for the Microwave Analysis of Unconventional Superconductors 1.1 Overview of Microwave Resonant Methods for the Characterization of Superconductors 1.1.1 Introduction: Resonant and Nonresonant Methods 1.1.2 Resonant Cavity and Resonant Cavity-Perturbation Methods 1.1.3 Dielectric Resonator Methods 1.1.4 Planar-Circuit Methods 1.1.5 Near Field Microwave Microscopy 1.2 A CPWR Technique for Thin-Film Analysis 1.2.1 CPWR Design, Measurements and Modeling 1.2.2 Extracting the Physical Parameters 1.3 A CPWR Technique for the Analysis of Single Crystals 1.3.1 Resonator-Perturbation Model 1.3.2 Calibration 1.3.3 Penetration Depth and Quasiparticle Conductivity References Part II Case Studies 2 Microwave Analysis of MgB2 and YBa2Cu3O7-x Thin Films 2.1 Two-Gap Analysis of the Surface Impedance of MgB2 CPWRs 2.2 Nonlinear Effects in MgB2 Films 2.2.1 Jumpwise Behaviors: Effects of Vortex Avalanches 2.2.2 Jumpwise Behaviors: Effects of Weak-Link Switching 2.3 Microwave Characterization of YBa2Cu3O7-x Films 2.3.1 Vortex-Induced Nonlinearity and Dissipation in YBa2Cu3O7-x CPWR 2.3.2 Tuning the Response of YBCO CPWRs by Heavy-Ion Irradiation References 3 Analysis of Microwave Conductivity and Penetration Depth of Iron Based Superconductors Families 3.1 Introduction 3.2 Comprehensive Analysis of K-, Co- and P-Substituted BaFe2As2 3.2.1 The Eliashberg Model Approach 3.2.2 Critical Temperature and Energy Gaps 3.2.3 Penetration Depth 3.2.4 Quasiparticle Conductivity 3.2.5 Nodes in the Energy Gap 3.3 Anisotropic Penetration Depth of CaKFe4As4 References 4 Effects of Disorder on Iron Based Superconductors 4.1 Foreword on the Relevance of Disorder Studies 4.2 Scaling Laws for Ion Irradiation Effects in IBS 4.3 Dependence on Chemical and Irradiation-Induced Disorder ... 4.4 Effects of Disorder on the Order Parameter Symmetry of Ba(Fe1-xRhx)2As2 References 5 Interplay Between Magnetism and Superconductivity in EuFe2(As1-xPx)2 Single Crystals 5.1 Coexistence of Superconducting and Magnetic Orders 5.2 Complex Magnetic Susceptibility of a Ferromagnetic Superconductor 5.3 Controlling Ferromagnetism with an External Magnetic Field 5.4 Tuning Superconductivity with Disorder References