Impact of Annealing on Flattening of Magnetic Entropy Change versus Temperature Curves in Amorphous and Partially Crystallized Fe76Mo10Cu1B13 Alloy

J. Świerczeka, A. Kupczyka, M. Hasiakb aInstitute of Physics, Częstochowa University of Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland bDepartment of Mechanics and Materials Science, Wrocław University of Technology, M. Smoluchowskiego 25, 50-370 Wrocław, Poland

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``Table-like'' shape of the magnetic entropy change versus temperature, ΔSM(T), curve in amorphous and partially crystallized Fe76Mo10Cu1B13 alloy has been investigated. The single ribbons in the as-quenched state and after annealing within the amorphous state exhibit ``caret-like'' behavior of ΔSM(T) near the Curie point, TC, of the amorphous phase. Amorphous Fe76Mo10Cu1B13 alloy shows the Curie point of 277 K in the as-quenched state. According to the invar effect TC decreases to 272 K and increases to 284 K after the annealing at 623 K and 673 K for 0.5 h, respectively. Layered composite consisting of annealed ribbons shows almost flat mathematically modeled ΔSM(T) curve in the temperature range from 262 K to 288 K. The temperature span ΔT=26 K is rather modest but takes place exactly in the ambient temperature range. The modeled values of ΔSM do not differ a lot from the maximum values of the single constituent. After the annealing at 823 K for 0.5 h ΔSM(T) curve for a single ribbon is flat in much wider temperature range than in the layered composite due to diversity of magnetic phases presented in the heat treated sample but ΔSM values drastically decrease.

DOI:10.12693/APhysPolA.135.212 PACS numbers: 75.50.Bb, 75.50.Kj, 75.60.Ej, 75.30.Sg