Synthesis, structure and magnetic entropy change of polycrystalline La1−xKxMnO3+δ

Magnetic entropy change in polycrystalline La1−xKxMnO3 perovskites

“…The relative strength of these two interactions can be strongly influenced by replacing La-ion by divalent/monovalent ion of different size and oxidation states which results in change of Mn 3+ /Mn 4+ ratio as well as Mn-O bond length and Mn-O-Mn bond angle. In case of polycrystalline La 1−x K x MnO 3 samples, substitution of smaller La 3+ ion (ionic radii ∼1.016Å) by larger K 1+ ion (ionic radii ∼1.33Å) increases the average ionic radius of La-site, thereby introduces crystallographic distortion and an increase in Mn-O-Mn bond angle [30]. This results in increased double-exchange interaction and a corresponding increase in T C of the system [31].…”

“…Magnetic entropy change on divalent alkaline-earth-doped lanthanide manganites with various compositions have been reported widely [3,4,12,[16][17][18][19][20][21][22][23][24][25][26][27][28]. However, investigations on monovalent alkali-metal-doped manganites are relatively few [7,29,30]. In the present communication, we report our recent results on the magnetocaloric effect in good quality La 1−x K x MnO 3 (x = 0.05, 0.10, 0.15), prepared by pyrophoric technique and having their T C ranging between 260 and 309 K. It is found that these materials display significant magnetic entropy changes induced by low magnetic field changes.…”

Magnetic entropy change in La0.67−Ca0.33MnO3

“…higher than that of La 0.67 Ca 0.33 MnO 3 . A possible interpretation is that the La site vacancy concentration influences the mean manganese valence and shortens the Mn-O bond distance and changes the Mn-O-Mn bond angle, which leads to a stronger interaction and gives a higher Curie temperature [10]. Fig.…”

Magnetocaloric effect above room temperature in the ordered double-perovskite Ba2Fe1+xMo1−xO6

“…Meanwhile, the hole-doped ABO 3 -type perovskite manganites perovskites [27,28] have also been found to generate large magnetic entropy change under a moderate magnetic field. In our recent systematic investigations carried out on magnetocaloric properties of perovskite materials, we have found many significant results [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Very recently, the basic research in the electronic and magnetic properties of the perovskite-type compounds of the type ABO 3 has been extended to compounds with ordered double-perovskite structure A 2 B 0 B 00 O 6 , in particular because magnetically ordered Sr 2 FeMoO 6 has shown a low-field colossal magnetoresistance remaining significant up to room temperature [29].…”