[sdpd] Problem with refinement of Ni-Zn ferrites

[Muhammad Ali <aliphy2008...@yahoo.co.uk>]

Respected Sir/Madam

Attached is the XRD's pattern. I have tried my best to solve this structure, but 

failed to do so. The refinement becomes unstable, when I try to perform Rietveld 

Refinement. I have to provide the information about the site occupancies in 
order to justify the electrical and magnetic properties of synthesized nano 
ferrites. If you can help me in this regard, i shall be very thankful to you for 

this act of kindness. Moreover, your name will be included as co-author (If you 
like). 


The sample information is as under
·         Chemical formula: Ni0.5Zn0.5Fe2O4
·         Total Number of Formula Units in a Unit Cell = 8
·         The ferrite structure is considered as closed packed structure of 
Oxygen, which has metal ions on the interstitial sites. The interstitial sites 
are of two types, Tetrahedral sites and Octahedral sites.
·         Crystal System: Cubic
·         Space group: Fd3m (space group #:227), Lattice 
parameter=8.40 angstroms
·         Coordinates for tetrahedral sites (x = 0.12500, y = 0.12500, z = 
0.12500)
·         Coordinates for Octahedral sites (x = 0.50000, y = 0.50000, z = 
0.50000)
·         Coordinates for Oxygen sites (x = 0.25490, y = 0.25490, z = 0.25490)

the other model that might be used to solve this structure is as follows.

STRUVIR (STRUPLO) data :

TITL Spinel MgAl2O4
CELL 8.089 8.089 8.089 90. 90. 90.
SPGR F D 3 M
VIEW 0 0 1
XYZR -0.25 1.25 -0.25 1.25 -0.25 1.25
OCTA 90 10 1.90 0.1
TETR 109 10 1.93 0.1
PARA 1 1 1 1 1 1 1 2.5
END
MG 1 0.125 0.125 0.125
AL 1 0.5 0.5 0.5
O 1 0.2633 0.2633 0.2633





Best Regards

Muhammad Ali Malik
Lecturer in Physics,
Govt. Degree College, Naushera,
Khushab, Punjab, Pakistan.


      

[Non-text portions of this message have been removed]



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