Spin-polarized tunneling and polaronic transport properties of polycrystalline (Sm1−yGdy)0.55Sr0.45MnO3 (y = 0.5 and 0.7) compounds. (10th June 2021)

• Record Type: Journal Article
• Authors: Mazumdar, Dipak; Das, Kalipada; Das, I
• Is Part Of: Journal of physics. Volume 33:Number 30(2021)
• Publication Date: 2021-06-10
• Subjects: meta-magnetic transition -- spin-polarized tunneling -- polaron hopping mechanism -- glassy-magnetic ground state -- ferromagnetic ground state -- magnetoresistance; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac0386
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The detail investigations on the magneto-transport properties of the polycrystalline (Sm0.3 Gd0.7 )0.55 Sr0.45 MnO3 (SGSMO-1) and (Sm0.5 Gd0.5 )0.55 Sr0.45 MnO3 (SGSMO-2) compounds, having a glassy-like and ferromagnetic ground states respectively have been carried out in details. Due to the existence of two different magnetic ground states in the above mentioned systems, the magneto-transport properties are markedly differed from each other, specially at the low temperature region. The highly semi-conducting nature of the SGSMO-1 compound is suppressed with the application of magnetic field, whereas the SGSMO-2 compound exhibits a metal–insulator transition in its pristine state. The high-temperature semiconducting state of both the systems can be well-explained with the polaronic transport mechanisms via small-polaron hopping and variable-range-hopping models. The low-temperature metallic states for both the systems are explored by considering the various contributions arise from the grain boundary effect, electron–electron, electron–phonon, electron-magnon etc scattering processes. The spin-polarized tunneling transport mechanism at the grain boundaries plays a crucial role in the enhancement of low-field magnetoresistance in the studied systems.