Large field longitudinal surface magnetooptical Kerr effect measuring apparatus

Abstract

The invention belongs to the optical technical field, in particular to a measuring device of magneto-optical kerr effect on longitudinal surface of a large field. The device consists of an electromagnet, a program control magnet power supply, a light path system and an operation control system (PC), wherein, the light path system subsequently consists of a semiconductor laser, a polarizing prism, a half transparent and half reflecting prism, a polarization detecting prism, a photodetector, a convex lens, a sample holder, an aperture, another polarization detecting prism, a long focal length convex lens and another photodetector; a magnetic filed for measurement is provided by the electromagnet which can provide a magnetic filed up to 1.5 tesla when the magnetic pole spacing is 4cm. The invention uses a converging convex lens to effectively expand the incident angle and the reflection angle of the light on the surface of the a sample, overcome the restriction of the magnetic pole spacing to the incident angle of the laser and enhance the magneto-optical kerr signal intensity on the longitudinal surface. The invention makes measurement of the high-coercivity magnetic film by the magneto-optical kerr effect possible.

Description

technical field [0001] The invention belongs to the field of optical technology measurement, in particular to a large-field longitudinal surface magneto-optical Kerr effect measurement device. technical background [0002] In 1877, John Kerr discovered the magneto-optical Kerr effect. According to the difference between the magnetization vector of the sample relative to the laser incident surface and the sample surface, the magneto-optic Kerr effect can be divided into three types: longitudinal Kerr effect, polar Kerr effect and transverse Kerr effect [1]. In 1985, Moog and Bader conducted magneto-optical Kerr effect measurements on ferromagnetic ultra-thin films, and successfully obtained the hysteresis loop of a magnetic material with a thickness of one atomic layer [2]. Since the measurement sensitivity of this method can reach the thickness of an atomic layer, it has become an important method for the study of surface magnetism. [0003] The following takes the longitu...

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Problems solved by technology

However, the high coercive force (5KOe--15KOe) of FePt-based thin film media makes it difficult to measure its magnetic properties. For the hysteresis loop along the vertical direction, it can be measured by the polar Kerr effect; The hysteresis loop in the direction can only be measured with a high-sensitivity vibrating sample magnetometer

This undoubtedly increases the difficulty of the research work

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