Shock Wave Compression of Nd$_{2}${Fe}$_{14}$B Hard Ferromagnets: The Pressure-Induced Magnetic Phase Transition

Recently, we developed a series of autonomous pulsed power sources that utilize the electromagnetic energy stored in hard ferri- and ferromagnetic materials. We present the results of experimental investigations of the demagnetization of Nd$_{2}$Fe$_{14}$B high-energy hard ferromagnets by explosive shock waves traveling across and along the magnetization vector \textbf{\textit{M}}. We show that shock wave compression of Nd$_{2}$Fe$_{14}$B ferromagnets causes a phase transition in the ferromagnetic material that results in almost complete demagnetization of the samples. Due to this phase transition the magnetostatic energy stored in Nd$_{2}$Fe$_{14}$B ferromagnets is released within a short time interval and can be transformed into pulsed power. Detailed experimental results are presented for both longitudinal and transverse shock wave demagnetization of Nd$_{2}$Fe$_{14}$B hard ferromagnets of different shapes and sizes.