Scaling Analysis of the Magnetocaloric Effect in Co/Au Nanoparticles
P. Hrubovčáka, A. Zeleňáková a, V. Zeleňák b and V. Franco c
aInstitute of Physics, Faculty of Sciences, P.J. Šafárik University, Park Angelinum 9, 041 54 Košice, Slovakia
bInstitute of Inorganic Chemistry, Faculty of Sciences, P.J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovakia
cDepartment of Condensed Matter Physics, University of Sevilla, P.O. Box 1065, 41080 Sevilla, Spain
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The system of superparamagnetic Co/Au bimetallic nanoparticles of average diameter 7 nm was investigated with respect to its magnetocaloric properties. DC magnetic measurements revealed the presence of field dependent zero field cooled M(T) maximum (6-8 K) and significant zero field cooled/field cooled irreversibility at low temperatures in the system. Documented thermal hysteresis disallow standard magnetic entropy change calculation from isothermal M(H) data, thus we attempted to employ zero field cooled M(T) data for this purpose. Magnetic entropy change was calculated employing the Maxwell relation. In maximal field variation of 1 T relative high magnetic entropy change for nanoparticles Δ SM ≈ 0.7 J/(kg K) at T =9 K was observed. The data collapsed onto single universal curve after proper axis rescaling.

DOI: 10.12693/APhysPolA.131.795
PACS numbers: 75.30.Sg, 75.75.Fk,