Abstract
In this paper the effect of Ca content in and the relation between electrostatic potential energy, critical temperature lattice parameters , volume lattice parameter , orthorhombicity, and the hole concentration is investigated by applying the ionic model to calculate the change in the electrostatic potential due to increasing the Ca content in the compound in . It is found that Ca2+substitution for Y3+ leads to increase EP caused by increased ion volume and decrease of charge, this explains changes of superconducting structure parameters such as: lattice parameter ,volume lattice parameter , orthorhombicity. Furthermore decreases with increasing Ca content due to increase of EP which leads to change of the crystal structure and thus decreasing oxygen content and as a result decreasing of Finally considering all above effects the increase of EP will increase the superconducting current.