مرکز منطقه ای اطلاع رساني علوم و فناوري - Mössbauer effect measurements of transferred hyperfine fields in Al-substituted Yttrium Iron Garnets

DocumentCode :

966555

Title :

Mössbauer effect measurements of transferred hyperfine fields in Al-substituted Yttrium Iron Garnets

Author :

Sauer, Ch. ; Zinn, W. ; Tolksdorf, W.

Author_Institution :

Institut für Festkörperforschung der Kernforschungsanlage Jülich, Jülich, W.Germany

Volume :

Issue :

fYear :

1978

fDate :

9/1/1978 12:00:00 AM

Firstpage :

701

Lastpage :

703

Abstract :

⁵⁷Fe Mössbauer effect studies of the hyperfine interactions in the dilution series Y3[Fe2-xAlx](Fe3-yAly)O12( $o\\leq(x+y)\\leq0.9$ ) confirm the predominant contribution of the inter-sublattice n.n. superexchange interaction between the Fe-ions at a- and d-sites. They also show that the intra-sublattice n.n.n. interactions have to be included to get meaningful results. The average transferred hyperfine filed contributions, $\\bar{\\Delta B_{a,d}}$ , and intrinsic h.f. field contributions, $B\\min{a,d}\\max {o}$ , at the $a$ - and $d$ - sites are $-(0.36plusmn0.1)T, -(0.32plusmn0.1)T, -(50.9plusmn1.4)T$ , and $-(45.4plusmn0.8)T$ , respectively. The ratio $\\Delta B\\min{d}\\max {d}/\\Delta B\\min{d}\\max {a}=0.3$ is consistent with a ratio $J_{dd}/J_{da}=0.089$ for the super-exchange constants and yields $\\Delta B\\min{d}\\max {a} - (0.6plusmn0.1)T$ being related with $J_{da} =22.5$ cm^-1. The isomer shifts, and, hence, the electronic configurations and h.f. coupling constants at the Fe³⁺ions are found independent of the Al-concentration $(x+y)$ .