Construction methods and techniques allow for a magnetic field of the field homogeneity required for the use in magnetic resonance imaging (MRI), in the order of 20 parts per million (ppm) in the area of interest (such techniques in the following will be indicated with the word “shimming”). The peculiarity of the constructive method is to obtain a homogeneous field region, usable for the MRI analysis, of linear dimensions equal to about 40% of the linear dimensions of the magnet. The shimming technique involves the use of conditioned magnetic material and allows accurate control of the magnetization of the corrective elements while using a material that inherently has a large spread in the magnetization value. The result is a low weight and small magnet suitable for MRI for dedicated clinical applications such as the analysis of the peripheral joint, the analysis of the ocular region, and veterinary applications.