General features of latent track formation in magnetic insulators irradiated with swift heavy ions

Abstract

A thermal spike model is proposed for the analysis of latent track formation in insulators. The model predicts that above a threshold electronic stopping power ${\mathit{S}}_{\mathit{e}\mathit{t}}$ ${\mathit{R}}_{\mathit{e}}^{2}$\ensuremath{\sim}ln${\mathit{S}}_{\mathit{e}}$ for 1\ensuremath{\le}${\mathit{S}}_{\mathit{e}}$/${\mathit{S}}_{\mathit{e}\mathit{t}}$\ensuremath{\le}2.7 followed by ${\mathit{R}}_{\mathit{e}}^{2}$\ensuremath{\sim}${\mathit{S}}_{\mathit{e}}$ for 2.7\ensuremath{\le}${\mathit{S}}_{\mathit{e}}$/${\mathit{S}}_{\mathit{e}\mathit{t}}$ (${\mathit{R}}_{\mathit{e}}$ being the effective track radius). A simple expression is derived for the evaluation of ${\mathit{S}}_{\mathit{e}\mathit{t}}$ from material parameters. A good agreement is found with literature data on latent tracks in magnetic insulators. The analysis showed that the width of the temperature distribution is a(0)=(4.5\ifmmode\pm\else\textpm\fi{}0.25) nm and the energy deposited in the spike is 0.17${\mathit{S}}_{\mathit{e}}$.