Please note that I do encourage doing "research" - it doesn't have to go all the way to an offer, but what I mean is to build confidence that you can indeed get one at the given salary. This is your BATNA, but because you're not giving an ultimatum, you don't have to walk away to a new job immediately - you can just start looking.
I would never tell my employer that I had another offer and was going to accept unless they met my demands. I'd keep it in my back pocket and then if they didn't respond to my treating them like an adult then I'd just inform them I was quitting and then I would. People who operate that way aren't worth working for!
I have never succeeded in getting any raise unless I had a concrete actionable BATNA, i.e. a competing offer.