We have studied the trapped field properties of the MgB_(2) bulk superconductors fabricated by various methods. The MgB_(2) bulks were magnetized by a filed-cooled magnetization (FCM) method using a superconductor coil and a pulsed field magnetization (PFM) method using a copper coil. We firstly obtained a trapped field of 1.5 T at 14 K by FCM for an MgB_(2) disc bulk (30 mm diameter and 7 mm thickness) with a filling factor of about 50 %, which was fabricated by an in-situ capsule method using a home-made capsule. The trapped field of MgB_(2) bulk by FCM was enhanced up to 2.9 T by the densification and the enlargement. Such dense MgB_(2) bulks were fabricated by an in-situ hot isostatic pressing under the pressure of up to 980 MPa or an ex-situ spark plasma sintering by applying uniaxial stress of 50 MPa. An in-situ infiltration method without the physical pressure also produced the dense MgB_(2) bulks, which trapped a 3 T-class magnetic field. The Ti-doping improved considerably the trapped field by FCM up to 5.6 T at 11.3 K for the triple-stacked Ti-doped MgB_(2) bulks. The PFM method also produced a Tesla-class MgB_(2) bulk magnet. The trapped field of 1.1 T at 13 K was obtained for the HIP-processed MgB_(2) disc bulk (22 mm diameter and 20 mm thickness). A magnetic field of 1.6 T was trapped at 20 K in the MgB_(2) bulk composite, consisting of two ring-shaped MgB_(2) bulks sandwiched by four thin copper plates and an inserted soft-iron yoke cylinder, using double PFM using a split-type coil with softiron yokes. We have shown the potential of the MgB_(2) bulk magnets for the practical superconducting applications.
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