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The Coercivity, also called coercive field or coercive force, is defined in a ferromagnetic material as the value of the applied external magnetic field to reduce the magnetization of a material (or sample) to zero after the sample has been magnetized to saturation. The magnetic parameter of Coercivity is a measure the resistance of a ferromagnetic material to becoming demagnetized.

ARkival measures the coercivity of magnetic material from a magnetic hysteresis loop measured with a vibrating-sample magnetometer (VSM). Coercivity is measured and reported in Oersted or ampere/meter units and denoted by Hc in the Hysteresis loop. In the VSM measurement, the coercivity Hc is measured by applying a (reverse) magnetic field  to reduce the sample magnetization to zero after the samples has been magnetized to saturation. Coercivity is defined from a Hysteresis loop at the point where H Field has a value at “0”. Ferromagnetic materials with high coercivity are called magnetically hard, and materials with low coercivity are said to be magnetically soft.

Curie Temperature

ARkival’s Curie temperature (Tc), or Curie point measurements are designed to determine the critical temperature at which magnetic materials loose their magnetic properties. Controlled temperature tests are performed in inert gas environments to determine the temperature (or temperature range) for which magnetic losses occur and the temperature below which magnetic properties return.

Magnetic forces defined by the materials’ magnet moment result from the materials atomic structure and the determination of the Curie temperature is the point or region which a material’s intrinsic magnetic moments disorient and randomly change direction.

Our lab facilities and magnetometers enable us to apply external magnetic fields during a controlled high temperature heating process while preventing material oxidation in an inert gas environment.