XAES measurements in -t.ile fem~r4tlitè range :20473 K ai Ihe F~,K,edge of synt.!ìeti<:: aìmandine (pe3:-\i2Sig01 V ' allow us to deterrùine thJ~T-pependen~ of the XAFSDebye-Waller (DW) Iactors fòr eachof the-twocrystallographically independent Fe'-Qbond dìstanees (Fe( 1)"0 and Fe{:ì).-Q). The XAFS DW factor of the longer Fe(2)-{)bondis 'Iarger and. has a grearer T-dependence ihan the shorter F~(l)-O bond, whieh reraains constant over the measured T ranae, The XAFS DW faetors are compared with the uncorrelared part of the DW factors derivcd from a single-crystal X-ray-diffraetipQ: .(XPJ) studiy on almandine and are interpreted.on the basis of theEinsìeìn .model. A cemparison with dìffractiorr data shows that the shoner Fe(l)-O bond is significantly affected by correlation in the atomic displacements.
Temperature dependence of disorder and correlation effects in almandine X-site: XAFS study and comparison with XRD data
ARTIOLI, GILBERTO;
1997
Abstract
XAES measurements in -t.ile fem~r4tlitè range :20473 K ai Ihe F~,K,edge of synt.!ìeti<:: aìmandine (pe3:-\i2Sig01 V ' allow us to deterrùine thJ~T-pependen~ of the XAFSDebye-Waller (DW) Iactors fòr eachof the-twocrystallographically independent Fe'-Qbond dìstanees (Fe( 1)"0 and Fe{:ì).-Q). The XAFS DW factor of the longer Fe(2)-{)bondis 'Iarger and. has a grearer T-dependence ihan the shorter F~(l)-O bond, whieh reraains constant over the measured T ranae, The XAFS DW faetors are compared with the uncorrelared part of the DW factors derivcd from a single-crystal X-ray-diffraetipQ: .(XPJ) studiy on almandine and are interpreted.on the basis of theEinsìeìn .model. A cemparison with dìffractiorr data shows that the shoner Fe(l)-O bond is significantly affected by correlation in the atomic displacements.
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