Production of Global Monopoles through the Nucleation of $O(3)$ Bubbles
  First-order cosmological phase transitions are considered in the models with an $O(3)$-symmetric scalar field, in the high temperature limit. It is shown that a global monopole can be produced at the center of a bubble when the bubble is nucleated. 
Yoonbai Kim, Kei-ichi Maeda and Nobuyuki Sakai