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A novel type of bi-constituent wire composite was obtained by combining melt-extracted Gd 50 Al 30 Co 20 and Gd 55 Al 20 Co 25 microwire components with Curie temperature ( T C ) of 86 K and 110 K, respectively. For a field change of 5 T, the wire composite possesses a table-like feature spanning a temperature interval of 30 K with value of ∼8.6 J kg −1  K −1 , and enhanced refrigerant capacity (RC) and relative cooling power (RCP) values of ∼680 J kg −1 and ∼863 J kg −1 , respectively. The experimental results agree well with those calculated by a simple bi-composition model, demonstrating the possibility of designing wire-based composites with desirable magnetocaloric effects (MCE) for active magnetic refrigeration. [ABSTRACT FROM AUTHOR]

We report enhancements of both Curie temperature and magnetic refrigerant capacity in Gd 50 (Co 69.25 Fe 4.25 Si 13 B 13.5 ) 50 microwires, which were fabricated by the melt-extraction method. For a field change of 5 T, the maximum magnetic entropy change (−Δ S M max ), the refrigerant capacity (RC) and relative cooling power (RCP) reached high values of 6.56 J kg −1 K −1 , 625 J kg −1 and 826 J kg −1 , respectively. While the RC is similar to those of our previously reported GdAlCo microwires, a much broader working temperature range of ∼126 K and a higher Curie temperature of 170 K make the Gd 50 (Co 69.25 Fe 4.25 Si 13 B 13.5 ) 50 microwires more attractive for active magnetic refrigeration. [ABSTRACT FROM AUTHOR]

High-quality Gd60Co15Al25 microwires with an average diameter of 40 µm were successfully fabricated by the melt-extraction method. The as-cast microwires undergo a second-order paramagnetic to ferromagnetic (PM-FM) transition at ∼100 K. Large values of the magnetic entropy change (−Δ SM ∼9.73 J kg−1 K−1) and the refrigerant capacity (RC ∼732 J kg−1) are achieved for a field change of 5 T. A careful analysis of critical exponents near the PM-FM transition indicates the significant effects of structural disorder on the long-range ferromagnetic interaction and the magnetocaloric response of the microwires. The excellent magnetocaloric properties make the Gd60Co15Al25 microwires very promising for use in magnetic refrigerators operating in the liquid nitrogen temperature range. [ABSTRACT FROM AUTHOR]

A new magnetocaloric composite composed of three types of soft ferromagnetic Gd‐based microwires with equal mass ratio and close magnetocaloric performances is designed. The Curie temperatures (TC) of these three wires are ≈97, ≈100, and ≈101 K, respectively. However, the magnetization versus temperature curve of the composite sample shows almost a single ferromagnetic–paramagnetic transition at ≈97 K. For a field change of µ0ΔH = 5 T, the maximum entropy change (−ΔSMmax) and refrigerant capacity (RC) of this composite are calculated to be ≈9.98 J kg−1 K−1 and ≈665 J kg−1, respectively. There is a good agreement between the calculated −ΔSM (T) curve and the experimental data, indicating weak magnetic interactions among different wire compositions. Additionally, the calculated universal master curves of the composite and its Gd‐Al‐Co components are fitted very well, which reveals the second‐order type of the magnetic transition for the composite. The designed composite integrates all magnetocaloric properties of its components, suggesting that the Gd‐based amorphous wires with close magnetocaloric properties can be designed as an excellent refrigerant for use in active magnetic refrigerators. [ABSTRACT FROM AUTHOR]

The enhanced magnetocaloric properties are studied in melt-extracted Gd 36 Tb 20 Co 20 Al 24 metallic glass microwires. The Curie temperature is ∼91 K for these microwires which show promising applications at liquid nitrogen range. The microwires possess spin glass phase in low temperature and spin freezing temperature is 60 K. Notably, the maximum magnetic entropy change (–Δ S M max), the relative cooling power (RCP) and the refrigerant capacity (RC) reach high values of 12.36 J kg−1K−1, 948 J kg−1 and 731 J kg−1, respectively, under a field change of 5 T. The large –Δ S M max originates from the high effective magnetic moment. Meanwhile, the spin fluctuation, the exchange integral fluctuation of metallic glass and the second order paramagnetic-ferromagnetic transition enlarge the phase transition range. Image 1 • Gd 36 Tb 20 Co 20 Al 24 metallic glass microwires were prepared by melt-extracted method. • The microwires show the maximum magnetic entropy change of 12.36 J. kg−1K−1. • The microwires exhibit refrigerant capacity of 731 J. kg−1. [ABSTRACT FROM AUTHOR]