Doing a dead-lift with a barbell is highly effective as the need to balance out the weight is very vital when it comes to training your core muscle. A barbell also allows you to carry more weight compared to a dumbbell as the latter do not usually come in such high weights and it requires more forearm strength in order to hold a pair of dumbbells that heavy.
A dead-lift should be done using light-weight first so that you get used to the motion of the exercise. I have seen cases where people sprain their back from a very bad form and very heavy weights. The idea behind a good dead-lift is to flex your back. But before we get ahead of ourselves, let us talk about the grip. A dead-lift should be held with an alternate grip, meaning one palm should face you while the other faces the front. Having this grip is advantageous because if one of the hands were to loosen the grip, the other will have to compensate and take the weight. This prevents an incident where the barbell will drop and land on your feet. The next thing to note is the grip width. A dead-lift should be held slightly longer than shoulder-width apart as it has to accommodate the space for the place where your legs are. A good dead-lift needs to move up and down the shin as close as possible so that most of the weight is transported by the back and not the shoulders.
Now let us talk about the form and how exactly is the exercise done. The dead-lift should resemble a squat; knees bent and in line with the ankle, back flat and not round with your chest flex and looking in front. Perfecting this form will ensure the weight is directed onto your lower back instead of other parts of the body. Keeping your back straight also tense the core muscles around your spinal column so that it will hold your spine in place. There is a usual habit to hyper-extend your back when you are standing up straight. Please do not do that as this will cause unnecessary pressure on your lower back as your core muscles can not be triggered once the hip is thrust forward. Stand up straight and lower the weight slowly until it is just slightly off the floor, pause and then lift back up again.