Abstract
The coercive force gradually increases as the temperature becomes lower than 730°, and suddenly increases when the temperature comes down to 550°. The remanent magnetization curve follows almost the same pattern as the coercive force-quenching temperature curve. In the magnetic analysis, the saturation-magnetization-temperature curve shows two distinct breaks at 550° and 730°, this curve being reversible both in heating and in cooling. The influence of field cooling is not effective when the specimen is cooled under a magnetic field from 500° down to 200°, but is effective when cooled from 570° to 200°.
