It was narrated from Ibn `Umar that :
the Messenger of Allah (ﷺ) entered into a contract with the people of Khaibar for one half of the fruits or crops yielded. (JA)
English reference (JA): Vol. 3, Book 16, Hadith 2467 (JA)
Arabic reference (JA): Book 16, Hadith 2561 (JA)