Effect of severe plastic deformation on the specific heat and magnetic properties of cold rolled Gd sheets

We report on specific heat and magnetic properties of thin Gd sheets obtained by means of a cold rolling technique. At temperatures well below Curie temperature T-C, the cold rolling has a minor impact on the specific heat C-p. However, a well defined lambda-type anomaly of C-p seen in the vicinity of T-C in a polycrystalline Gd sample is markedly suppressed in the severely deformed samples. Depression of the lambda peak is due to a large decrease of magnetization that presumably originates in a local magnetic anisotropy induced by the severe plastic deformation. Results of calculation of magnetocaloric effect from the C-p and magnetization data indicate that the magnetocaloric effect gradually decreases as the degree of plastic deformation increases. This trend is further confirmed by the direct measurements of the adiabatic temperature change Delta T-ad. (C) 2015 AIP Publishing LLC.