FIELD: electromagnetic logging of holes by method of nuclear magnetic resonance. SUBSTANCE: logging sonde carries antenna forming high-frequency magnetic field in formations around sonde and receiving signals characterizing emergence of nuclear magnetic resonance in examined formations and magnet creating permanent magnetic field in examined formations. Magnet is manufactured from powder material displaying conduction and properties of permanent magnet. Size of particles in this material with due account of frequency of high-frequency magnetic field is quite small and essentially prevents onset of intragrain power loss of high-frequency magnetic field in magnet. Magnet is fabricated form individual blocks of magnetic material electrically insulated one from another, thickness of blocks is less than skin depth of penetration of high-frequency magnetic field into magnetic material. Orientation of faces of adjacent blocks secures formation of breaks in circuit of potential flow of eddy currents through magnet emerging under effect of high-frequency magnetic field. In preferable version magnetic material presents samarium-cobalt alloy bound by epoxy resin. EFFECT: reduced losses in permanent magnet related to eddy currents. 25 cl, 6 dwg
