Аннотация:Highly effective materials are created for solid-state magnetic cooling in the range below room temperature (120–280 K). An investigation is performed of new (R,R')(Co,T)2 and R(Mn,T)Si (T = Fe, Co, Al) compounds and hydrides based on them that have a notable magnetocaloric effect (MCE) in the region of the Curie temperature. Main patterns of the behavior of an MCE depending on composition are revealed.