Magnetic and electrical properties by Ca2+ doping in SmCrO3 orthochromites

•In the 150 - 300 K range, resistivity data were fitted to a small-polarons mechanism.•Ca2+ doping in SmCrO3 reduces from TN = 192.3K (x=0) to 150K (x = 0.20).•Both TN and TRS values depend almost linearly on the Ca2+ content.•The Γ2(Cx, Gy, Fz) phase is the only one present for the x = 0 and 0.02 c...

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Bibliographic Details
Published in:Journal of alloys and compounds 2022-01, Vol.890, p.161823, Article 161823
Main Authors: Tavizon, Gustavo, Barreto, Jorge, Mata-Ramírez, Jorge, Huerta, Lázaro, Arenas, Jesús, de la Mora, Pablo, Duran, Alejandro
Format: Article
Language:English
Subjects:
Ca doped SmCrO3
Calcium ions
Charge transfer
Electrical measurement
Electrical properties
Ferromagnetic phases
Ferromagnetism
Low temperature
Magnetic properties
Magnetization curves
Orthochromite
SmCrO3
SmCrO3 crystal structure
SmCrO3 electrical properties
SmCrO3 magnetic properties
SmCrO3 Rietveld refinements
Spectrum analysis
X ray photoelectron spectroscopy
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Summary:•In the 150 - 300 K range, resistivity data were fitted to a small-polarons mechanism.•Ca2+ doping in SmCrO3 reduces from TN = 192.3K (x=0) to 150K (x = 0.20).•Both TN and TRS values depend almost linearly on the Ca2+ content.•The Γ2(Cx, Gy, Fz) phase is the only one present for the x = 0 and 0.02 compositions at 5 K. [Display omitted] Spectroscopic (UV–vis and XPS) magnetic and electrical properties of the Ca2+ doped SmCrO3 system were phenomenologically investigated. The Cr3+, Cr5+, and Cr6+ species were identified by XPS spectroscopy in Sm1−xCaxCrO3 (0 ≤ x ≤ 0.20). Rietveld analyses of the X-ray diffraction data reveal a smooth decrease in the cel`l parameters assigned to the Cr6+ formation as a function of the Ca2+ content. Diffuse reflectance spectroscopy showed that the wider optical bandgap of the system corresponds to a charge transfer process, and it disappears for x ≥ 0.1, showing t2 g-eg electronic gaps. The electrical measurements were fitted in two temperature ranges; for low temperatures (85–150 K), a 3D variable-range hopping mechanism seems to prevail, while for the 150–300 K range, the electrical behavior is well represented by the small-polarons conduction mechanism. Magnetic properties of Sm1−xCaxCrO3 were highly sensitive to the Ca2+ content, and the TN values varied from 192 to 151 K for x = 0 and x = 0.20, respectively; TRS varied from 34 to 9 K for the same x values. Isothermal magnetization curves at 5 K suggest that, as a function of the Ca2+ content, the Γ4 ferromagnetic phase remains for x ≥ 0.04; while for x = 0 and x = 0.02, the Γ2 ferromagnetic phase is the only one observed.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2021.161823