Hysteresis loss is one of the important behaviors to be considered which reverse the magnetization. In this study, the influence of alloying element, grain size, particle size and spark plasma sintering on hysteresis loss (HL) has been analyzed. An increment in the % of nickel caused a decrement in HL value at 2–100 h milling time. Generally, the value of HL decreases with the decrement of average grain size, however, the value of HL is observed to marginally increase while the average grain size decreases from 225 to 75 nm. A maximum HL value was found with the average grain size 75 nm. Hence, it could be concluded that up to a critical average grain size of ∼75 nm the HL is not strongly dependent on the average grain size, whereas lower the grain size from 75 nm the HL value steeply decreases. It indicates the high HL value can be observed at intermediate grain size and low HL value at fine and coarse grain sizes. The HL value is higher at the intermediate average size of the particle and becomes lower while the average size of the particle with a larger or smaller dimension. It was found from all spark plasma sintering samples that when milling hour increases the value of HL increases, because of the increment in sintered grain size at higher hour milled samples and also decreases the lattice imperfection and internal strain while sintering.
