Probing the Griffiths like phase, unconventional dual glassy states, giant exchange bias effects and its correlation with its electronic structure in Pr2-xSrxCoMnO6

TL;DR

This study investigates the electronic, magnetic, and transport properties of Pr2-xSrxCoMnO6, revealing complex magnetic phases, mixed valence states, and giant exchange bias effects linked to electronic structure and disorder.

Contribution

It uncovers the emergence of a new cluster glass phase driven by Sr doping and correlates magnetic phenomena with electronic structure and disorder in Pr2-xSrxCoMnO6.

Findings

Presence of Griffiths-like phase above magnetic ordering temperature

Emergence of a Sr doping-driven cluster glass phase

Observation of giant exchange bias effects

Abstract

Electronic structure, electrical transport, dc and ac magnetization properties of the hole substituted (Sr2+) partially B-site disordered double perovskite Pr2-xSrxCoMnO6 system have been investigated. Electronic structure was probed by employing X-ray photoemission spectroscopy (XPS) measurements. The study suggested the presence of mixed valence states of the B-site ions (Co2+/Co3+ and Mn3+/Mn4+) with significant enhancement of the average oxidation states due to hole doping. The mere absence of electronic states near the Fermi level in the valence band (VB) spectra for both of the pure (x=0.0) and Sr doped (x=0.5) systems indicated the insulating nature of the samples. Sr substitution is observed to increase the spectral weight near the Fermi level suggesting for an enhanced conductivity of the hole doped system. The temperature variation of electrical resistivity measurements revealed the insulating nature for both the systems, thus supporting the VB spectra results. The dc magnetization data divulged a Griffiths like phase above the long range ordering temperature. A typical re-entrant spin glass like phase driven by the inherent anti-site disorder (ASD) has been maidenly recognized by ac susceptibility study for both the pure and doped systems. Most interestingly, the emergence of a new cluster glass like phase (immediately below the magnetic ordering temperature and above the spin-glass transition temperature) solely driven by the Sr substitution has been unravelled by ac magnetization dynamics study. The isothermal magnetization measurements further probed the exhibition of the giant exchange bias effect emanated from the existence of multiple magnetic phases.