K dopant effect on La 0.7K xCa 0.3 - xMnO 3 (x= 0 , 0.05, 0.1) perovskite compounds: the structural, magnetic and magnetocaloric properties

Abstract

La 0.7K xCa 0.3 - xMnO 3 (x= 0 , 0.05, 0.1) perovskites were prepared by sol–gel method. The K-doped effect was determined by the structural, magnetic, and magnetocaloric properties of the compounds. In the crystal structure of K-doped La 0.7Ca 0.3MnO 3, Mn–O–Mn bond angle slightly increases with K addition. The transition shifts the range of 270–320 K when the K is added in La 0.7Ca 0.3MnO 3. The Curie temperature increases from 251 to 288 K with increasing K amount. The maximum magnetic entropy change was found to be 2.7 J kg-1K-1 at 283 K under a magnetic field change of 2 T for the La 0.7K 0.05Ca 0.25MnO 3. The relative cooling powers (RCPs) in the La 0.7K xCa 0.3 - xMnO 3 (x= 0 , 0.05, 0.1) samples were calculated to be 103, 133 and 88 J kg- 1, respectively. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.