The young defender completed his transfer on Sunday afternoon.
Posting to social media, Hato declared: "It's difficult to find the right words, because Ajax is my home. From the moment I joined the club as a boy, I dreamed of playing in the Johan Cruijff ArenA. Thanks to your support and the trust of everyone at the club, that dream has come true.
"After seven wonderful years, it's time to take a new step in my career. This wasn't an easy decision, because Ajax shaped me as a footballer and as a human being. I want to thank everyone: my coaches, my teammates, the people behind the scenes, and of course the supporters who have always supported us through thick and thin.
"Ajax will always have a special place in my heart and will always remain an Ajacied, wherever I am. Thank you, Amsterdam, forever home."