In the idealized cubic unit cell of such a compound, type'A'atom sits at cube corner positions ( 0, 0, 0 ), type'B'atom sits at body centre position ( 1 / 2, 1 / 2, 1 / 2 ) and oxygen atoms sit at face centred positions ( 1 / 2, 1 / 2, 0 ) . ( The diagram shows edges for an equivalent unit cell with A in body centre, B at the corners, and O in mid-edge ).
12.
:: : : In the case of iron ( Fe ), a phase change occurs at 1183 K ( from body centred to face centred ), but the Curie point is below this at 1043 K . The resistivity curve follows Worthing's formula accurately ( better than +,-1 % ) with P = 1.768 up to the Curie point then continues with P close to unity up to and past 1183 K . There may be an inflection point at 1183 K but it is difficult to detect in measured data . ( A paper by V E Zinovev & others in the Soviet Journal of Physics in 1972 claimed a slight step at about 1200 K but to my knowlege this hasn't been replicated.
