Let's get a few things straight before we go any further.
First of all, I suggest you find a good definition of "material". Here's one - the substance or substances of which a thing is made or composed. Here's another - anything serving as crude or raw matter for working upon or developing.
Now let's talk about you. What field are you qualified in or interested in? Are you an engineer, a chemist or other scientist for example?
You see kobi, you can spend a lifetime working as a textile researcher examining fabric everyday of the way for little more than the minimum wage. Yes, textile researchers are materials researchers. On the other hand, you could spend your days researching aspects of radioactive elements in a hi-tech lab with state-of-the-art facilities and get paid a pretty reasonable wage for your efforts.
You could work in the Patent Office, which is another interesting job and is reasonably well paid.
All these jobs are "material researchers" and you need to appreciate that you'll never get a true answer to your question unless you're a lot more specific than you've been so far.
What do you mean by "researching different kinds of materials". Are you implying that you think material researchers test fabric one day and uranium samples the next? Sorry, it doesn't happen like that and besides, you're not going to find a "How to become a Materials Researcher" book in your careers library, believe me.
(continued)