Crystal structure and magnetocaloric effect of non-rare-earth KBa8Fe12(Bi6-xFex)O38

The 6p orbit coupling of bismuth ions and the magnetism of iron ions endow bismuth-iron compounds with magnetic, optical and electrical properties. In this paper, non-rare-earth bismuth-iron crystals, KBa8Fe12(Bi6-xFex)O-38 (x = 0.2, 1.1, 2.0, 2.9, and 3.8), with a large magnetocaloric effect were prepared by a hydrothermal method. The structure-function relationship is discussed. With the increase of the Fe content, the lattice parameters and unit cell volume decrease, while the magnetization intensity shows an increase on the whole and a fluctuation at the same time. The increase of the Fe content can improve the magnetocaloric effect. Importantly, the maximum magnetic entropy change (Delta S-M) of KBa8Fe12(Bi4.9Fe1.1)O-38 is as high as 1.54 J kg(-1) K-1 at the low temperature of 2 K.

Automated summary

The synthesis of non-rare-earth bismuth-iron crystals via hydrothermal method showed that with increasing iron content, the lattice parameters decrease, magnetization intensity increases, and the maximum magnetic entropy change also improves.