The nature of the magnetocaloric effect (MCE) in compounds R2Fe14B (R = Nd, Er) and their hydrides in a wide temperature range is investigated. The investigation is carried out on initial samples of a special purity including single-crystalline ones.
The highest value of the magnetocaloric effect is established in the Curie-temperature region. The hydrogenation of samples affects the value of the MCE.
The model explaining the dependence of the value and sign of the magnetocaloric effect on the hydrogen contents in R2Fe14B compounds with participation of erbium and neodymium is proposed.