  The magnetocaloric effect (MCE) of A-site ordered PrBaMn2O6 manganite has
been studied by direct methods and by the specific heat measurements. Direct
measurements of the MCE in low magnetic fields were performed using recently
proposed modulation technique and by classic direct method in high fields.
Direct and inverse MCE are observed at Curie and Neel points correspondingly. A
value of the inverse MCE in the heating run is less than in the cooling regime.
This effect can be attributing to competition between ferromagnetic and
antiferromagnetic interactions. Indirectly estimated and direct MCE values
considerably differ in around first order AF transition.
