1969 Volume 10 Issue 6 Pages 375-382
The longitudinal magnetostriction has been studied at ordinary temperatures in the thermally demagnetized state and in the alternating-current demagnetized state with two rod specimens of iron containing 0.5% Al, using the optical lever method. One of the specimens is a single crystal whose rod axis is situated between [100] and [110], called the [210] specimen, and the other a polycrystal made of the raw material used for the preparation of single crystals. It has been found that the magnetostrictive behavior of the [210] specimen is as a whole intermediate between the behaviors of the [100] and [110] specimens, and consequently shows a strong dependence on the method of demagnetization. On the contrary, it has been noted that the magnetostrictive behavior of the polycrystal specimen is as a whole similar to that of the [110] specimen in a thermally demagnetized state, but there is a considerable difference between them in that the dependence of the magnetostrictive behavior on the method of demagnetization in the former is far less than in the latter. Furthermore, in both the [210] specimen and the polycrystal the difference of magnetostriction between the state of remanent magnetization and that of magnetic saturation is independent of the method of demagnetization. In addition, the value of the magnetostrictive constant, λ111, of these specimens is −20.5×10−6, as determined in consideration of the difference of magnetostriction between the two states described above.
