Mujahid (may Allah have mercy on him) narrates from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that he disliked talking after Fajr, or the narrator said: he considered talking after the two rak'ahs of Fajr disliked (makruh); and he considered the takbir and tasbih recommended.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3033