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Dynamic mesoscale model of the metamagnetic transition in low-bandwidth perovskite manganites
Tekijät: J. Tikkanen, H. Huhtinen, P. Paturi
Kustantaja: AMER PHYSICAL SOC
Julkaisuvuosi: 2017
Journal: Physical Review B
Tietokannassa oleva lehden nimi: PHYSICAL REVIEW B
Lehden akronyymi: PHYS REV B
Artikkelin numero: ARTN 014405
Vuosikerta: 96
Numero: 1
Sivujen määrä: 8
ISSN: 2469-9950
DOI: https://doi.org/10.1103/PhysRevB.96.014405
Tiivistelmä
Using bulk magnetometry, it was experimentally verified that the metamagnetic insulator-to-metal transition observed in the perovskite manganite Pr1-xCaxMnO3 (PCMO) occurs at different critical values of the magnetic-field strength, depending on the macroscopic geometry of the sample in the absence of applied elastic strain. In dimensionally confined samples, such as nanoparticles and thin films, the critical magnetic field can be lower than in bulk by several teslas. To gain a practical understanding of the mechanism behind this correlation, a phenomenological mesoscale simulation was developed to model and analyze the magnetic hysteresis of PCMO. It could be concluded that the low-dimensional samples have a well-defined, permanent free energy bias towards ferromagnetism, something the largely antiferromagnetic bulk all but lacks. The metamagnetic transition field of PCMO turns out to be globally minimized when no external elastic strain is applied and the smallest spatial dimension of the sample approaches 100 nm. The result is likely to apply equally to other low-bandwidth manganites.
Using bulk magnetometry, it was experimentally verified that the metamagnetic insulator-to-metal transition observed in the perovskite manganite Pr1-xCaxMnO3 (PCMO) occurs at different critical values of the magnetic-field strength, depending on the macroscopic geometry of the sample in the absence of applied elastic strain. In dimensionally confined samples, such as nanoparticles and thin films, the critical magnetic field can be lower than in bulk by several teslas. To gain a practical understanding of the mechanism behind this correlation, a phenomenological mesoscale simulation was developed to model and analyze the magnetic hysteresis of PCMO. It could be concluded that the low-dimensional samples have a well-defined, permanent free energy bias towards ferromagnetism, something the largely antiferromagnetic bulk all but lacks. The metamagnetic transition field of PCMO turns out to be globally minimized when no external elastic strain is applied and the smallest spatial dimension of the sample approaches 100 nm. The result is likely to apply equally to other low-bandwidth manganites.
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