UNDERGRADUATE ENGINEERING STUDENT LABORATORY: STANDARD PHYSICS EXPERIMENT PLUS BONUS

The paper describes a laboratory experiment intended for undergraduate students of Electrical Engineering as part of a general 1st year physics course. In the course of the measurement, students determine the Curie temperature of iron. The Curie temperature is a physical constant and refers to a characteristic property of ferromagnetic materials. Above the Curie temperature, a material loses its ferromagnetic properties. In a ferromagnetic material, elementary dipoles are aligned into the so - called domains and the domains - through their arrangement - bring about the internal magnetic field of the material magnetization. At temperatures above the Curie point the ordered state is destroyed, magnetic dipoles become chaotically disordered and the material no more exhibits ferromagnetic properties. This change comes about in an abrupt manner at reaching the Curie temperature. Magnetic domains and their behavior under action of an external magnetic field belong to frequent questions of students. In order to facilitate the understanding of this phenomenon, magnetic domains are visualized and observed in a microscope under variable external magnetic field.