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<span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small"><span style="color: red; font-size: 12pt;"><span style="color: black;">Answering your question of NiO with a P lattice;
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If you take a P structure with 4 Ni and 4 O then you can flip two Ni atoms and you have an antiferro in the 100 direction, which is not the one that you sent in the figure</span></span><br style="font-size: 12pt;">
<span style="font-size: 12pt;">In my earlier message you can see the antiferro ordering in the 111</span>.<br>
<span style="font-size: 12pt;">Both of these structures are frustrated</span>, <span style="font-size: 12pt;">
that is, you cannot put an antiferromagnetic ordering in which the nearest Ni atoms are always antiparalle</span><span style="font-size: 12pt;">l</span>.<br>
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<p>First, we can create the structure of Cr with 2 ways:<br>
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<div>1- with one atom and bcc lattice (0,0,0) or<br>
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2- with two atoms and P lattice (0,0,0) and (.5,.5,.5)<br>
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But the second way allows us to do the antiferromagnetic calculation by flipping the spins of one atom.<br>
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Second, the same thing, normally, for the Ni element.<br>
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We can produce the structure with 2 ways:<br>
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1- with one atom and fcc lattice (0,0,0) or<br>
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2- with four atoms and P lattice (0,0,0) (1/2,1/2,0) <span style="color:red; font-size:x-large">
<span style="color:black; font-size:large"><span style="font-size:small">(0,1/2,1/2) (1/2,0,1/2)<br>
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<span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small">Here we can flip the spins of the two atoms of Ni to do the antiferromagnetic calculation.<br>
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<span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small">Third, i want to do the same thing with the NaCl structure (NiO) . I have to get two atoms of Ni at least to reproduce the same crystal structure.
And starting with this structure i will determine the equilibrium parameters.<br>
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<span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small">the question still how to reproduce the NaCl structure with two or four atoms of Ni so we can do antiferromagnetic calculation with this structure.<br>
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</span></span></span><span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small"><span style="color: red; font-size: 12pt;"><span style="color: black;">*** </span></span></span></span></span><span style="color:red; font-size:x-large"><span style="color:black; font-size:large"><span style="font-size:small"><br>
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<div>-- <br>
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<div><font><span style="color:rgb(0,0,255)">Mr: A.Reggad</span>
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<span style="background-color:rgb(238,238,238)"><span style="color:blue">Laboratoire de Génie Physique</span></span><br>
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<font><span style="color:rgb(0,0,255)">Université Ibn Khaldoun - Tiaret</span><br>
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<div><font><span style="font-family:monospace"><span style="color:rgb(0,0,255)">Algerie</span></span></font><br>
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