Get excel table from web site using httr GET

How could i extract excel table from web site, using username and password which i have using httr? I tried this, but it doesn't work:

url <- "https://ss0.corp.com/auth"
login <- "john.johnson" (fake)
password <- "67HJL54GR" (fake)

res <- GET(url, authenticate(login, password))
content <- content(res, "text")

But it doesn't give me the excel table. Content doesn't give me excel. After i log in there there appears a button which allows to download excel table. But i get a list of numbers, like 5,8,3,6,7,8b,9a,2,5t,..... Even when i paste wrong password the output is the same. What do i do wrong and how it must look like?