Abstract: A magnetic screw having a screw shaft of magnetic material having thread crests formed on the outer peripheral surface thereof, and a magnetic nut fitted on the outer periphery of the screw shaft. The magnetic nut includes annular permanent magnets magnetized with magnetic poles of opposite polarities on opposed sides, and annular yokes disposed such that the annular yokes are magnetically coupled with the magnetic poles of the magnets. The inner peripheral surfaces of the yokes are provided with thread crests corresponding with the thread crests of the screw shaft with a minute gap G defined therebetween such that magnetic circuits are formed between the screw shaft and the magnets through the thread crests of the screw shaft. The magnets are magnetized on their inner and outer radial surfaces with magnetic poles of opposite polarities, and the yokes are fitted in the magnets.

Abstract: The invention provides a cavity resonator for an electron spin resonance device in which modulation coils for generating a modulation magnetic field to be applied to a sample in the cavity resonator are arranged at an exterior of the cavity resonator. The cavity resonator comprises a body being rectangular-defined by predetermined length, width and height. The body has a pair of side walls being vertical to the modulation magnetic field. The side wall respectively have at least thin portions of a thickness being nearly equal to or less than a skin depth of a skin effect appearing at the side walls. The modulation coils are arranged on the thin portions so as to have the modulation magnetic field be transmitted through the thin portions into the interior of the cavity resonator. Alternatively, it is possible that inner walls of the body are overlaid with metallic foils having at least sufficiently smaller thickness than a skin depth of a skin effect appearing at the walls.

Abstract: In a fixed polarized magnetic field generated by permanent magnets 10, a cylindrical cavity resonator 12 and a coil 14 modulating the magnetic field are provided. A micro-wave f generated from a micro-wave oscillator 16 is supplied through an isolator 18 and a subsequent attenuator 20 and then a circulator 24 to the cavity resonator. The oscillation output of a modulating frequency oscillator 42 is supplied to the coil 14. A movable end plate 60 is moved by a driving feature 58 to vary the resonance frequency f.sub.0 for a detection thereof and a subsequent negative feed back to a micro-wave oscillator 16 through a circuit comprising a low frequency amplifier 48, a phase detector 50, a low frequency oscillator 54, a phase shifter 56 and a micro-wave oscillator power source 52 thereby the micro-wave frequency f is so swept as to be maintained to be equal to the resonance frequency f.sub.0.

Abstract: The invention provides an electron spin resonance device in which a measuring sample is arranged in a cavity resonator in a polarization magnetic field for a receipt of a predetermined microwave power and a subsequent resonance signal detection from said sample. A microwave signal amplifier is arranged on a prestage of a microwave detection circuit for an addition of a part of an output from a microwave oscillator at an input terminal of said amplifier so as to accomplish a balanced cancellation of a microwave reflective power from said cavity resonator.