Magnetization and magnetocaloric effect in ball-milled zinc ferrite powder

Abstract

Enhancement of magnetocaloric effect (MCE) in nanostructured materials is important for refrigeration applications such as spot cooling in microelectromechanical system devices. Here we report the first investigation of MCE properties in ball-milled ZnFe2O4 particles. The MCE was obtained by measuring a family of M-H curves at set temperature intervals and calculating the entropy change (ΔS) for this system using the Maxwell relation. The surface structure of zinc ferrite particles is sensitive to ball milling conditions and we observed that these surface effects greatly impact the MCE and our observations could provide a route for its potential enhancement by controlled surface modification.

Inverse magnetocaloric effect in sol–gel derived nanosized cobalt ferrite

“…There are reports wherein giant inverse MCE has been observed in alloys like NiMnSb Heusler alloys [28,29]. A positive entropy change has been recently reported in zinc ferrite nanoparticles [30].…”

Preparation and microstructure of spinel zinc ferrite ZnFe2O4 by Co-precipitation method

“…The results show that the pure spinel zinc ferrites ZnFe 2 O 4 are formed when the Zn/Fe molar ratio is 1.05∶2 at pH＝8.5 or Zn/Fe molar ratio is 1∶2 at Ph＝9-10, and the precursors are sintered at 1100 Spinel zinc ferrite ZnFe 2 O 4 has attracted more attentions due to its interesting magnetic property and application in the photocatalysis [1][2][3][4][5][6][7][8] . Its magnetic property is mainly determined by its microstructure which is affected by the synthesis conditions and methods [9][10][11][12][13][14] . Many methods, such as traditional ceramic synthesis [15] , hydrothermal synthesis [10,[16][17][18] , sol-gel techniques [19][20][21] , co-precipitation [22][23][24] , mechanical milling [11,25] , etc, have been used to fabricate the precursors, which dramatically affect the crystal sizes and sintering temperature.…”

Magnetic entropy change in bulk nanocrystalline Gd metals

“…Considerable investigations indicate that the nanostructured materials are very promising candidates for potential application in the magnetic refrigeration (Zhang et al 2001;Tanaka et al 2001;Hueso et al 2002;Provenzanoa et al 2003;Shir et al 2003;Kinoshita et al 2004;Evangelisti et al 2005;Poddar et al 2006;Gómez-Polo et al 2007;Ma et al 2007;Baldomir et al 2007;Franco et al 2007;škorvánek et al 2007;Poddar et al 2007;Biswas et al 2008;Franco et al 2008;Gorsse et al 2008;Li 2008;Gass et al 2008;Lu et al 2008;Santanna et al 2008;Serantes et al 2008;Pekała and Drozd 2008;Juan and Gui 2009;Gorria et al 2009;Phan et al 2009;Babita et al 2009;Calderon-Ortiz et al 2009;Das et al 2009;Phan et al 2010;Burianova et al 2010;Nelson et al 2002). However, up to now, not much effort has been devoted to the rare earth bulk nanocrystalline metals.…”