Details

Autor(en) / Beteiligte

• Ruan, M.Y.
• Yang, C.Q.
• Wang, L.
• Jin, P.B.
• Guo, Z.L.
• Wei, X.L.
• Wu, W.X.

Titel

Size-dependent magnetocaloric effect in GdVO4 nanoparticles

Ist Teil von

• Journal of alloys and compounds, 2022-02, Vol.894, p.162351, Article 162351

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Nanocrystal GdVO4 presents enhanced paramagnetic-like behavior with the reduction of grain size.•The enhanced paramagnetic-like behavior leads to a giant entropy change of -ΔSM = 45 J/kg K at 3 K for Δ = H = 7 T.•The decrease of the saturated magnetization and -ΔSM with the grain size reduce to 30 nm is due to the aggregation effec.•Introducing paramagnetism in AFM materials provides a promising way to adjust the magnetic entropy of these materials. We investigated the magnetization and electron spin resonance (ESR) in nanocrystals of antiferromagnet GdVO4 with the grain size ranging from 30 nm to 5 µm. Our nanoparticles with an average size reduction from 5 µm to 300 nm exhibited enhanced paramagnetic-like behavior, in which the weakly coupled spins can be well aligned along the direction of an external magnetic field, resulting in a giant entropy change of -ΔSM = 45 J/kg K at 3 K for ΔH = 7 T. Moreover, with a further reduction of grain size to ~ 30 nm, the saturation magnetization together with the negative entropy change -ΔSM, max decreased dramatically. The aggregation effect is believed to be responsible for the decline in -ΔSM, max, in which small nanoparticles agglomerating to ‘large’ grains made them behave like bulk material. Finding the critical point of positive size effect on magnetocaloric effect offered a new way to achieve large magnetic entropy change.