I have read about an amal (Thikr consisting of Durood Shareef and Qur'aanic Surahs) to be recited after Zuhr Salaat.

Answer

The amal should be recited after having completed the Sunnat and Nafl Salaat, not after the Fardh.It should be remembered that amals should never be recited after any Fardh Salaat if there are Sunnat Salaat after the Fardh. Ittisaal (i.e. performing the Sunnatul Muakkadah Salaat immediately after the Fardh) is Waajib. It is not permissible to recite anything in between the Fardh and Sunnatul Muakkadah Salaat. Only the short Sunnat Dua may be recited. From this should be understood that the new innovation of kitaab-reading immediately after Fardh Salaat, thus compelling the musallis to sit and delay the Sunnat Salaat, is not permissible. It is a new bid'ah which should be abandoned.