A1 Refereed original research article in a scientific journal
Appearance of glassy ferromagnetic behavior in Gd1-xCaxMnO3 (0 <= x <= 1) thin films: A revised phase diagram
Authors: Schulman A, Beiranvand A, Lähteenlahti V, Huhtinen H, Paturi P
Publisher: ELSEVIER
Publication year: 2020
Journal: Journal of Magnetism and Magnetic Materials
Journal name in source: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Journal acronym: J MAGN MAGN MATER
Article number: ARTN 166149
Volume: 498
Number of pages: 6
ISSN: 0304-8853
eISSN: 1873-4766
DOI: https://doi.org/10.1016/j.jmmm.2019.166149(external)
Abstract
We report on results of electrical transport properties of Gd1-xCaxMnO3 (0 <= x <= 1) thin films fabricated on top of SrTiO3 substrates by pulsed laser deposition. The lowest studied doping level (x < 0.1) was enough to trigger a transition from the antiferromagnetic state present in the parent compound (x = 0) to a ferrimagnetic state. Up to x = 0.3, the system exhibits a high temperature insulator paramagnetic state and a low temperature insulator ferrimagnetic one. At higher concentrations, the electrical and magnetical properties of the films differ drastically from the bulk form which shows a strong antiferromagnetic behavior. At mid Ca substitution (0.4 <= x <= 0.7), samples show a high temperature charge ordered state with ordering temperatures around room temperature and a low temperature glassy state which was not observed in their bulk counterparts. In contrast, high x samples show a high temperature conductive paramagnetic state and a low temperature insulator antiferromagnetic phase. More interestingly, sample x = 0.9 shows a distinct minimum in the resistivity versus temperature plots and a region of thermal hysteresis which indicate a first order transition. Magnetoresistance measurements display a strong irreversibility which we attributed to phase separation effect of a kinetically arrested ferromagnetic metallic phase and a stable antiferromagnetic insulator phase. Based on the above observations and previous magnetic results, we have reconstructed a phase diagram and characterized the properties of each phase.
We report on results of electrical transport properties of Gd1-xCaxMnO3 (0 <= x <= 1) thin films fabricated on top of SrTiO3 substrates by pulsed laser deposition. The lowest studied doping level (x < 0.1) was enough to trigger a transition from the antiferromagnetic state present in the parent compound (x = 0) to a ferrimagnetic state. Up to x = 0.3, the system exhibits a high temperature insulator paramagnetic state and a low temperature insulator ferrimagnetic one. At higher concentrations, the electrical and magnetical properties of the films differ drastically from the bulk form which shows a strong antiferromagnetic behavior. At mid Ca substitution (0.4 <= x <= 0.7), samples show a high temperature charge ordered state with ordering temperatures around room temperature and a low temperature glassy state which was not observed in their bulk counterparts. In contrast, high x samples show a high temperature conductive paramagnetic state and a low temperature insulator antiferromagnetic phase. More interestingly, sample x = 0.9 shows a distinct minimum in the resistivity versus temperature plots and a region of thermal hysteresis which indicate a first order transition. Magnetoresistance measurements display a strong irreversibility which we attributed to phase separation effect of a kinetically arrested ferromagnetic metallic phase and a stable antiferromagnetic insulator phase. Based on the above observations and previous magnetic results, we have reconstructed a phase diagram and characterized the properties of each phase.
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