Enhancement of magnetocaloric effect around room temperature in Zn0.7Ni0.3-xCuxFe2O4 (0 ≤ x ≤ 0.2) spinel ferrites

摘要: Abstract In this work, a profound study has been conducted on magnetocaloric effect in Zn0.7Ni0.3-xCuxFe2O4 (with x = 0, 0.1 and 0.2) spinel ferrites synthesized by the sol-gel method. The Rietveld analysis of powder X-ray diffraction shows that samples crystallize cubic system with Fd 3 ¯ m space group. Structural lattice constant unit cell volume increase increasing Cu content. Magnetization measurements versus temperature magnetic applied field 0.05 T show our exhibit paramagnetic (PM)-ferromagnetic (FM) transition decreasing temperature. partial substitution Ni leads to monotonic decrease Curie (TC) from 327 K for x = 0–282 K x = 0.2. Additionally, Arrott plots Landau theory were also studied assess phase ordering these materials, such investigations indicate PM FM states is second order. entropy change | Δ S M max takes values 0.67, 0.64 0.62 J/kgK x = 0.2, respectively at 2 T. relative cooling power (RCP) amounts 111, 117 124 J/kg 2T respectively. Because relatively easy possibility tuning TC interesting power, can be considered as suitable candidates refrigeration around room