Pressure-induced structural, magnetic, and transport transitions in the two-legged ladder Sr3Fe2O5

Year: 2011 DOI: 10.1021/ja200410z

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Takafumi Yamamoto, Cédric Tassel, Yoji Kobayashi, Takateru Kawakami, Taku Okada, Takehiko Yagi, Hideto Yoshida, Takanori Kamatani, Yoshitaka Watanabe, Takumi Kikegawa, Mikio Takano, Kazuyoshi Yoshimura, Hiroshi Kageyama.   Journal of the American Chemical Society, 2011, 133, 6036-6043.


The layered compound SrFeO(2) with an FeO(4) square-planar motif exhibits an unprecedented pressure-induced spin state transition (S = 2 to 1), together with an insulator-to-metal (I-M) and an antiferromagnetic-to-ferromagnetic (AFM-FM) transition. In this work, we have studied the pressure effect on the structural, magnetic, and transport properties of the structurally related two-legged spin ladder Sr(3)Fe(2)O(5). When pressure was applied, this material first exhibited a structural transition from Immm to Ammm at P(s) = 30 ± 2 GPa. This transition involves a phase shift of the ladder blocks from (1/2,1/2,1/2) to (0,1/2,1/2), by which a rock-salt type SrO block with a 7-fold coordination around Sr changes into a CsCl-type block with 8-fold coordination, allowing a significant reduction of volume. However, the S = 2 antiferromagnetic state stays the same. Next, a spin state transition from S = 2 to S = 1, along with an AFM-FM transition, was observed at P(c) = 34 ± 2 GPa, similar to that of SrFeO(2). A sign of an I-M transition was also observed at pressure around P(c). These results suggest a generality of the spin state transition in square planar coordinated S = 2 irons of n-legged ladder series Sr(n+1)Fe(n)O(2n+1) (n = 1, 2, 3, ...). It appears that the structural transition independently occurs without respect to other transitions. The necessary conditions for a structural transition of this type and possible candidate materials are discussed.[on SciFinder (R)]