An apparatus comprising: an active magnetic regenerative regenerator comprising multiple successive layers, wherein each layer comprises an independently compositionally distinct magnetic refrigerant material having Curie temperatures 18-22 K apart between successively adjacent layers, and the layers are arranged in successive Curie temperature order and magnetic refrigerant material mass order with a first layer having the highest Curie temperature layer and highest magnetic refrigerant material mass and the last layer having the lowest Curie temperature layer and lowest magnetic refrigerant material mass.