Structural, magnetic and magnetocaloric effects in epitaxial La<subscript>0.67</subscript>Ba<subscript>0.33</subscript>Ti<subscript>0.02</subscript>Mn<subscript>0.98</subscript>O<subscript>3</subscript> ferromagnetic thin films grown on 001-oriented SrTiO<subscript>3</subscript> substrates.
In: Dalton Transactions: An International Journal of Inorganic Chemistry, Jg. 45 (2016-10-14), Heft 38, S. 15034-15040
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Zugriff:
Epitaxial La0.67Ba0.33Ti0.02Mn0.98O3 (denoted as LBTMO hereafter) thin films of approximately 95 nm thickness were deposited by a pulsed laser deposition technique onto SrTiO3 (STO) (001) substrates. High-resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM) investigations revealed that the films are epilayers with a four-fold symmetry around the [001] direction. Cross-sectional TEM and the presence of Pendellosung fringes in the XRD profiles demonstrate smooth interfaces. The STO substrate induces an in-plane compressive strain, which leads to a slight tetragonality of the film structure. The epilayers exhibit paramagnetic-to-ferromagnetic phase transitions at the Curie temperature TC (286 K), close to room temperature. The magnetization easy axis lies in the film plane along the [100] direction of the (001) substrate. The magnetic entropy change (ΔSM) associated with the second-order magnetic phase transition was determined via magnetization measurements in the temperature range between 210 and 350 K under different magnetic fields. The relative cooling power (RCP) of this film is about 220 J kg−1, somewhat lower than that of bulk Gd (410 J kg−1) for a 50 kOe field change, making the LBTMO ferromagnetic thin films a promising candidate for micro/nanomagnetic refrigeration around room temperature. The proposed universal curve provides a simple method for extrapolating ΔSM in a wide range of fields and temperatures, thus confirming the order of the magnetic transition in this system. The magnetic entropy (ΔSM)max around TC is proportional to (μ0H/TC)2/3 in agreement with the mean-field theory, indicating the existence of long-range ferromagnetic interactions in epitaxial LBTMO thin films. [ABSTRACT FROM AUTHOR]
Titel: |
Structural, magnetic and magnetocaloric effects in epitaxial La<subscript>0.67</subscript>Ba<subscript>0.33</subscript>Ti<subscript>0.02</subscript>Mn<subscript>0.98</subscript>O<subscript>3</subscript> ferromagnetic thin films grown on 001-oriented SrTiO<subscript>3</subscript> substrates.
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Autor/in / Beteiligte Person: | Oumezzine, Marwène ; Galca, Aurelian Catalin ; Pasuk, Iuliana ; Chirila, Cristina Florentina ; Leca, Aurel ; Kuncser, Victor ; Tanase, Liviu Cristian ; Kuncser, Andrei ; Ghica, Corneliu ; Oumezzine, Mohamed |
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Zeitschrift: | Dalton Transactions: An International Journal of Inorganic Chemistry, Jg. 45 (2016-10-14), Heft 38, S. 15034-15040 |
Veröffentlichung: | 2016 |
Medientyp: | academicJournal |
ISSN: | 1477-9226 (print) |
DOI: | 10.1039/c6dt01914e |
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