Is atonement for an oath fulfilled by feeding ten poor people rice and meat, where the amount of rice is a quarter of a kilogram or less, knowing that it will likely be sufficient for the individuals, or must the feeding be repeated with 750 grams of rice?

Scholars differ concerning the obligatory amount for expiation of an oath. Some stipulated the transfer of a specific amount of food to the poor (a mudd or half a saa'), while others held it permissible to feed the poor two meals (lunch and dinner). There is another opinion that considers the obligation to be satiating the needy, even with a single meal. This is the view preferred by Sheikh al-Islam Ibn Taymiyyah and Sheikh Ibn Uthaymeen. Based on this, what you did by feeding ten needy people one meal is sufficient according to this opinion. However, it is better to feed them another meal or to transfer to them the obligatory amount to avoid the اختلاف (disagreement among scholars).