Mössbauer effect study of SrEu_{2}Fe_{2}O_{7}
Abstract
The antiferromagnetic ferrite SrEu_{2}Fe_{2}O_{7} was studied by Mössbauer effect of^{57}Fe in the range 77 650 K. Analysis of the data gives a Neel temperature of 544 K±2 K and an extrapolated effective magnetic field H(OK) of 545 kG. Good fit to the spectrum at 290 K is obtained with H _{eff}=475 kG, δ=0.37 mm/s, 1/2 e ^{2} qQ(1+ η ^{2}/3)=0.70mm/s, θ and ϕ=90°. The Brillouin function for S=5/2 poorly fits the experimental data of hyperfine magnetic fields. In the critical range H _{eff} can be described by H(T)=H(0) D(1 T/T _{ N })^{β}, where β nearly 0.29. The quadrupole interaction parameter is quite temperature independent, of the order of 0.69 mm/s in the paramagnetic state. Agreement with the value obtained by a point charge calculation is good. The largest axis of the EFG tensor, V _{ zz }, lies in the plane (110), making an angle of 22.6° with the c axis. The direction of magnetization is nearly perpendicular to V _{ zz } in [110] direction.
 Publication:

Applied Physics
 Pub Date:
 October 1976
 DOI:
 10.1007/BF00920596
 Bibcode:
 1976ApPhy..11..159H
 Keywords:

 Crystal Structure;
 Iron Isotopes;
 Mossbauer Effect;
 Neel Temperature;
 Temperature Effects;
 Brillouin Effect;
 Crystallography;
 Europium Compounds;
 Laminates;
 Magnetic Fields;
 Spectrum Analysis;
 Strontium Compounds;
 SolidState Physics;
 PACS Code 76;
 76