Application of MMMA method: Dispersed superconductors and magnetic nanolayers

Abstract

Abstraet. Microwave nonresonant dissipation observed around zero field makes a powerful method in characterizing superconducting state (to determine Tc, Hcl , Hcj parameters). This review shows several successful applications of magnetically modulated microwave absorption (MMMA). M M M A enables to study MgB 2 superconducting nanoregions embedded in the Mg host structure. Application of MMMA to study intercalation of fullerene enabled the observation of a new superconducting phase.The pressure effeet dTc/d p has been studied below the percolation threshold in YBaCuO/PST composites. The local temperature of the Josephson junction measured by the MMMA technique showed that a granular superconductor consists of two phases: host phase and Josephson junction system. MMMA has been applied lately to separate the giant magnetoresistance from the magnetization effect in differential hysteresis loops.

Magnetic field modulated microwave spectroscopy across phase transitions and the search for new superconductors

“…It was observed that the superconductors and materials exhibiting a strong change in the magnetoresistance [90] produce a similar derivative signal when the magnetic field is swept. However, it was shown that the hysteresis of the low-field absorption signal can be used to differentiate superconducting transitions from magnetic transitions [91][92][93]. A comprehensive comparison of temperature sweep signals for various types of phase transitions has not been reported.…”