Mazumdar D, Das K, Das I. Spin-polarized tunneling and polaronic transport properties of polycrystalline (Sm
1-yGd
y)
0.55Sr
0.45MnO
3(
y= 0.5 and 0.7) compounds.
JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021;
33:305601. [PMID:
34015772 DOI:
10.1088/1361-648x/ac0386]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
The detail investigations on the magneto-transport properties of the polycrystalline (Sm0.3Gd0.7)0.55Sr0.45MnO3(SGSMO-1) and (Sm0.5Gd0.5)0.55Sr0.45MnO3(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.
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