A probe head for nuclear magnetic resonance measurements in an area of a surface of a measuring object is disclosed. The probe head comprises first means for generating a static magnetic field extending at least partially parallel to the surface, second means for generating a radio frequency magnetic field having components extending perpendicular to the surface, and third means for amplifying a radio frequency magnetic field effective within the measuring object. The third means are configured as an aperture and are located between the second means and the surface.