It is narrated from al-Qasim bin Muhammad, Salim bin Abdullah, Abu Bakr bin Abd al-Rahman, Sulayman bin Yasar and Ibn Shihab (may Allah have mercy on them) that they all used to say concerning this that when a divorced woman enters the blood of her third menstruation, she has become separated from her husband. There is no inheritance between the two of them, and it is not permissible for the husband to take her back. Imam Malik (may Allah have mercy on him) said: This is what I found the people of knowledge in our city upon.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15391