Recently, our neutron scattering experiments on electron doped BaFe2-xNixAs2 and hole doped Ba1-xKxFe2As2 suggest that the presence of both high-energy spin excitations giving rise to a large magnetic exchange coupling and low-energy spin excitations coupled to the itinerant electrons is essential for high-Tc superconductivity in iron pnictides. To further confirm this conclusion, it would be important to study the spectrum of spin excitations as a function of isovalent doping. For this purpose, we have prepared BaFe2-2xNixCrxAs2 single crystals codoped by Ni and Cr. We thus propose to measure the spin excitations in BaFe1.8Ni0.1Cr0.1As2 compound, corresponding to the optimal electron doped BaFe1.9Ni0.1As2 but without superconductivity.The outcome will illustrate the difference between superconducting and nonsuperconducting samples near the same electron-doping.