In the paper we present and discuss magnetic properties of the Tb(Ni_{1-x}Fe_{x})_{3} (x=0.2, 0.6) crystalline compounds and their ball-milled powders. The investigated samples are polycrystalline and crystallize in the rhombohedral PuNi_{3} type of crystal structure. The Curie temperature of the material seems to be independent of particle size and is constant. The coercivity depends on the amount of iron dopant. The saturation magnetization decreases after mechanical grinding which is connected with the reduction in particle size. After 6 h milling time the SEM results show the presence of nanoflakes with thickness up to 100 nm or even smaller. Moreover, the pulverization leads to the observed decrease of magnetocaloric effect.
The influence of substitution of Co for Ni in Sm(Ni_{1-x}Co_{x})₃, where x=0.0, 0,1, 0.2, on the structural and magnetic properties has been investigated. Samples with x= 0.0 and 0.2 were subjected to grinding in a high energy ball mill. The presence of a PuNi₃ type of crystal phase was evidenced for bulk crystalline and powders specimens. With an increase in the cobalt content, an increase at T_{c} was observed. From the magnetic isotherms, the magnetic entropy changes were determined both for solid and powdered samples. It has been shown that the value of the magnetic entropy change at T_c is doubled for the bulk sample with x= 0.2 but it has decreased significantly for all powdered samples.
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