The knot quandles of Suciu's ribbon $n$-knots and automorphisms on the free group of rank two

Jab{\l}onowski proved that the knot quandles of Suciu’s $n$-knots, which share isomorphic knot groups, are mutually non-isomorphic, and Yasuda later gave a different proof. In this paper, we present yet another proof of this result by analyzing the conjugacy classes of certain automorphisms of the free group of rank two.