Isovalent-substitution effect on the Verwey-type transition in the A-site-ordered double perovskite (Ba,Sr)RFe2O5

J. Nakamura, M. Karppinen*, P. Karen, J. Lindén, H. Yamauchi

*Korresponderande författare för detta arbete

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

5 Citeringar (Scopus)

Sammanfattning

Two types of chemical-pressure effects on the Verwey-type transition in BaSmFe2O5 are studied, viz., ionic-size contractions at the Ba and Sm sites. Whereas the replacement of Sm by the smaller Eu and Gd atoms increases the transition temperature TV from 232 K to 264 K, the Sr-for-Ba substitution decreases it from 232 K to 180 K for x=0.15 in (Ba1-xSrx)SmFe2O5. Of various structural parameters determined by synchrotron x-ray diffraction above T V, the magnitude of the orthorhombic distortion (=b-a) is found to correlate with TV in a manner that unifies both substitution schemes. It is suggested that when an increase in b-a above TV is achieved by means of the structural substitution, it makes it easier for the dxz Fe2+ orbital ordering to occur below TV.

OriginalspråkEngelska
Artikelnummer144104
Sidor (från-till)144104-1-144104-6
TidskriftPhysical Review B - Condensed Matter and Materials Physics
Volym70
Utgåva14
DOI
StatusPublicerad - okt 2004
MoE-publikationstypA1 Tidskriftsartikel-refererad

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