Abstrakti
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.
| Alkuperäiskieli | Englanti |
|---|---|
| Artikkeli | 144104 |
| Sivut | 144104-1-144104-6 |
| Julkaisu | Physical Review B - Condensed Matter and Materials Physics |
| Vuosikerta | 70 |
| Numero | 14 |
| DOI - pysyväislinkit | |
| Tila | Julkaistu - lokak. 2004 |
| OKM-julkaisutyyppi | A1 Julkaistu artikkeli, soviteltu |
Rahoitus
This work was supported by Grants-in-aid for Scientific Research (Nos. 15206002 and 15206071) from the Japan Society for the Promotion of Science. The synchrotron radiation experiments were performed under the auspices of SPring-8 (PRC No. 2002B0170). Professor Satoshi Sasaki and Dr. Ken-ichi Kato and Dr. Kouji Yamawaki are thanked for their experimental guidance.
Sormenjälki
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