Magneto-optical imaging of polycrystalline FeTe1−xSex prepared at various conditions

► High-quality FeTe1-xSex polycrystals with Tc ∼ 14 K were prepared by sintering at different temperatures. ► Intragranular critical current density of FeTe1-xSex polycrystals estimated from M-H curve is 5 × 104 A/cm2 at 5 K under zero field. ► The observed intragranular Jc value was confirmed by the magneto-optical images in the remanent state. ► The weak-link feature of FeTe1-xSex polycrystals is also revealed through magneto-optical imaging.