The word "motivation", in psychology is the intention of achieving a goal, leading to goal-directed behavior.
In this view the general conclusion is that leadership is motivation and motivation is leadership, and that the two elements are inseparable. However, interestingly, no one has actually conceptualized motivation in a useful way to demonstrate and analyze the connection between it and leadership.
While Motivation clearly comes under personality and emotion, Leadership comes under cognitive psychology. But basically, belief is the solution to the problem.