The effect of ionic substitution on the E.P. of La2-xSrxCuO4 superconductor using madelung method

الملخص EN

The effect of substitution of the ion 2 Sr instead of La+3 in the superconductor 2 4 La Sr CuO x x was studied, an increase in electrostatic potential energy E.

P.

(E) with increase of Sr % was noticed, and a step change in P.

E.

when Sr is added is noticed indicating a phase change occurrence in the crystal structure .Increase of Tc, with the increase of Sr, noticed earlier, is linked with increase of E.P.

and a relation between E.P.

and Tc is found 2 T 90.227 6.604E 1.545E c    , the increase of Tc is due the creation of holes by valance difference between La & Sr, which also leads to collapse of crystal by reduction of repulsion between Sr & Cu atoms this have the same effect as the application of pressure on the crystal, which increases Tc also.

For x >0.15, Tc decreases due to the appearance of vacancies which may have screening effect of the electrostatic field.