[Unity] Rotating over time

   IEnumerator RotateAxisY()
    {
        while (true)
        {
            var currentRotation = transform.localRotation;
            var newRotation = currentRotation * Quaternion.AngleAxis(rotationSpeed,Vector3.down);
            for (float t = 0; t < 0.5f; t += Time.deltaTime)
            {
                Quaternion rotation = Quaternion.Slerp(currentRotation, newRotation,t * 2);
                transform.localRotation = rotation;
               // yield return null;
            }

            transform.localRotation = newRotation;
            yield return null;
        }
    }