Publication Date:
2016-01-01
Description:
A study of the magnetocaloric effect for Tm 2 Fe 16 , Tm 2 Fe 17 , Tm 2 Fe 18 , Tm 2 Fe 19 , Tm 2 Fe 17− x Mn x ( x ≤ 1.5), Ce 2 Fe 17− x Mn x H y ( x 〈 2, y ≤ 3), Lu 2 Fe 17− x Mn x ( x ≤ 2) systems at magnetic ordering temperatures T C , T N and a ferro-antiferromagnet phase transition Θ T , from magnetization measurements. In alloys with ground ferromagnetic and high-temperature antiferromagnetic states, the change in the magnetic entropy peak −Δ S M increases as the magnetic phase transition temperatures Θ T and T N converge with varying compound composition. Extrapolating the difference T N − Θ T to zero for the initial and doped alloys allows us to determine the maximum possible value of −Δ S M in such systems and the composition of the corresponding alloy. A superposition of the −Δ S M (T) maxima at Θ T and T N for compounds with two magnetic phase transitions creates much higher values of relative cooling power in comparison to compounds with only one magnetic phase transition at T C .
Print ISSN:
1063-777X
Electronic ISSN:
1090-6517
Topics:
Physics
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