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

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 Sₑₜ Rₑ²{~}lnSₑ for 1{≤}Sₑ/Sₑₜ{≤}2.7 followed by Rₑ²{~}Sₑ for 2.7{≤}Sₑ/Sₑₜ (Rₑ being the effective track radius). A simple expression is derived for the evaluation of Sₑₜ 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±{}0.25) nm and the energy deposited in the spike is 0.17Sₑ.