In a recent article, an alternating field-gradient magnetometer was described [P. J. Flanders, J. Appl. Phys. 63, 3940 (1988)]. For calibration of the system, a calculation was carried out. Here, the treatment of the extension rod of that system and the considerations concerning the piezoceramic are criticized.
D. Cabra, C. Gazza, A. Dobry, and T. Vekua. Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)