Effect of Zn on magnetic and magnetocaloric properties in (0.75)La0.62Nd0.05Ba0·33MnO3/(0.25)Ni1-Zn Fe2O4 composites

The magnetocaloric effect properties for potential applications of magnetic refrigerator technology: a review

“…The calculation of RCP is related to the value of −Δ S M and can be defined as follows: 9,41,44 RCP = |−Δ S max M | × δ T FWHM where, −Δ S max M is the maximum magnetic entropy change from −Δ S M and δ T FWHM is the full width at half maximum (FWHM) of −Δ S M curve. This approach presents some problems, such as certain samples having wide −Δ S M ( T ) curves with very small −Δ S M values or narrow −Δ S M ( T ) curves with very high −Δ S M values.…”

“…Perovskite manganites (PM) are ceramic materials with the general formula R 1− x A x MnO 3 , where R represents rare earth metals, trivalent elements such as La, Pr, Nd, Sm, Eu, Gd, Ho, Tb, Y and A represents elements such as monovalent elements (Li, Na, K, Ag, etc) 4,15 and divalent elements (Mg, Ca, Sr, Ba, etc) 41,44,113 which have been extensively combined. The mixed element combinations of PM will create a mixed valence at site A or B.…”

“…They also reported the value of the RCP which had a good value with ranges of 242, 252.72, 300.60 for x = x = 0.5, 0.6, 0.7. 44…”

“…To date, innovative types of materials include Heusler alloys, 28,29 LaFe 13− x Si x alloys, 30–33 Fe-based alloys, 34 MnAs, 35 spinnel ferrites, 36–38 perovskite magnanites, 9,15–17,27,39–41 double perovskites, 19 and composite. 42–44 This was aimed at obtaining MCE materials with ideal criteria for magnetic refrigeration applications. Based on the criteria proposed by Phan et al , perovskite manganites have the potential as a permanent magnetic refrigeration applications.…”