High-quality Gd 60 Co 15 Al 25 microwires with an average diameter of 40 mm were successfully fabricated by the meltextraction method. The as-cast microwires undergo a secondorder paramagnetic to ferromagnetic (PM-FM) transition at $100 K. Large values of the magnetic entropy change (ÀDS M $9.73 J kg À1 K À1 ) and the refrigerant capacity (RC $732 J kg 1 Introduction Magnetic refrigeration (MR) based on the magnetocaloric effect (MCE) of magnetic refrigerant materials with a first-order magnetic transition (FOMT) or a second-order magnetic transition (SOMT) has attracted growing interest in the scientific community, due to its advantages (e.g., high-cooling efficiency, environmental friendliness, low noise, and compactness) over conventional gas compression-based cooling techniques [1]. Beside Gd, one of the best refrigerant candidates for sub-room temperature magnetic refrigeration [2], a large number of alloys including GdSiGe [3], LaFeSi [4], and MnFePAs [5] exhibiting giant MCEs have been developed for roomtemperature MR, and some of them have also been exploited in low-temperature MR [6]. It has been reported that the larger magnetic enetropy change (DS M ) is observed in a FOMT material but is concentrated in a narrower temperature range, as compared to a SOMT material that shows the smaller magnetic entropy change over a broader temperature range [7]. As a result, the larger refrigerant capacity (RC), which depends both on the magnitude of DS M and on