Open AccessA brief discussion of the magnetocaloric effect in thin films of manganite doped with chromium
Author(s) -
G. Campillo,
A. I. Figueroa,
O. Arnache,
J. Osorio,
J. M. Marín Ramírez,
Lorenzo Fallarino
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1247/1/012013
Subject(s) - magnetic refrigeration , manganite , materials science , condensed matter physics , curie temperature , magnetic circular dichroism , magnetization , ferromagnetism , paramagnetism , antiferromagnetism , orthorhombic crystal system , analytical chemistry (journal) , sputter deposition , thin film , sputtering , crystallography , chemistry , magnetic field , crystal structure , nanotechnology , physics , spectral line , chromatography , quantum mechanics , astronomy
In this work we report on the magnetocaloric effect of La 2/3 Ca 1/3 MnO 3 (LCMO) and La 2/3 Ca 1/3 Mn 0.94 Cr 0.06 O 3 (LCMCrO) manganite thin films grown by DC magnetron sputtering on LaAlO 3 (100) substrates. X-ray diffraction shows that both doped and undoped films crystallize in the orthorhombic structure. Magnetic measurements show a decrease in both the Curie temperature, T C , and the saturation magnetization, M S , for the LCMCrO sample. The change in the magnetic entropy (Δ S m ) was extracted from hysteresis loops at different temperatures around the ferromagnetic to paramagnetic transition, displaying a maximum of entropy change (Δ S m ) max near T C in both films. Moreover, a shift in (Δ S m ) max toward temperatures above T C with increasing magnetic field and a broadening of the entropy change curve were observed. Results of refrigeration cooling power show a lower efficiency for LCMCrO. In order to obtain a local insight into the magnetic interactions of these films, measurements of X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) were performed. XMCD suggests that an antiferromagnetic coupling between Mn 4+ - Mn 3+ is favored with Cr 3+ incorporation, which reduces the Mn L 2,3 XMCD signal and results in a decrease of M S and (Δ S m ) max in LCMCrO films.