I would like to place my mother in a facility, but she is refusing. She has been diagnosed with Alzheimer's. Any advice?

Technically I think your father has more ability to place her. As spouse he can make decisions as well. How does he feel about placing her? And if he is in declining health would they consider a move together? If he has help there are cases where someone with dementia does well in Assisted Living if they are with the spouse. If dad also has dementia then both into Memory care would not be a bad idea.

Me too, I placed Mom into an AL with just my POA. I didn't even have a formal diagnosis they could very well tell Mom had Dementia when they evaluated her for care.

“I’m told that’s not enough…..”? Told by WHOM?

I did exactly what you’re describing when my LO entered an AL, and definitely didn’t need conservatorship.

Find out THEIR SOURCE from your source, and ask why your tools aren’t enough.

It's not quite clear to me if you are the PoA or someone else is.

If you are her PoA then you read the document to see what is required for the authority to be active. If you meet the criteria, you don't need conservatorship, just need to understand that getting her to cooperate may not be a thing and you may need to create a therapeutic fib to get her there: "The house has an infestation and you must leave for a while. I'm taking you and Dad to a temp apartment." Or, "There's a gas leak that is dangerous..." etc. Whatever it takes whatever you think she'll buy.

You can talk to the admin at the facility so that they can participate. They've done it before, guaranteed. You will need to figure out how to get her furnishings there in advance, but it can and has been done before by others.