Equiatomic FeRh alloy has been electrolytically hydrogenated in order to in
duce volume expansion. After the hydrogenation, differential scanning calor
imetry shows a 40% decrease in enthalpy of the antiferromagnetic-ferromagne
tic transformation which is in agreement with the magnetization increase me
asured in a SQUID magnetometer. This result is analysed in terms of conduct
ion band polarisation in a periodic array of localised moments. (C) 1999 El
sevier Science B.V. All rights reserved.