On the broadening of the magnetic entropy change due to Curie temperature distribution.

We have studied the correlation between the broadening of the isothermal magnetic entropy change and the Curie temperature (TC) distribution in nanostructured Pr₂Fe₁₇ and Nd₂Fe₁₇ alloys produced by high-energy ball-milling after milling times of 10, 20, and 40 h. The changes in the microstructure affect the Fe local environments and as a consequence the magnetic interactions, giving rise to TC distributions centered around 285K and 330K for the Pr₂Fe₁₇ and Nd₂Fe₁₇ alloys, respectively. The width of the distributions enlarges (up to 60K) as the milling-time increases, and consequently, the isothermal magnetic entropy change curves show an extended full width at half maximum. [ABSTRACT FROM AUTHOR]