Multiple graphs output using `{tikzDevice}` to a single tex file in R

Question

I want to output graphs to a single tex file using {tikzDevice}, I wrote following loop trying to make it happen:

library{tikzDevice}

graphList <- list(...) # ... are the graphs I have made using ggplot2

for (i in 1:length(graphList)) {

    cat("\\begin{figure}\n", file = "GraphList.tex", append=TRUE)
    sink("GraphList.tex", append=TRUE)

    tikz(console = TRUE)
    graphList[[i]]
    dev.off()

    sink()

    cat(paste0("\\caption{", names(graphList)[[i]],"}",sep=" "), 
    file = "GraphList.tex", append=TRUE)
    cat("\\end{figure}\n", file = "GraphList.tex", append=TRUE)
 }  

Sometimes it works but sometimes does not by just writing what I put in the cat part into tex file without graphs.

I am pretty newbie to this, could anyone help me out of here? Many Thanks!

Updated:

The following code works (Suppose I only have 2 graphs in list for example):

   sink("Output/graph/GraphList.tex", append=TRUE)

   tikz(console = TRUE)
   cat("\\begin{figure}\n")
   graphList[[1]]
   cat(paste0("\\caption{", names(graphList)[[1]],"}",sep=" "))
   cat("\n\\end{figure}\n")

   cat("\n\\begin{figure}\n")
   graphList[[2]]
   cat(paste0("\\caption{", names(graphList)[[2]],"}",sep=" "))
   cat("\n\\end{figure}\n")

   sink()

So my wild guess is that R does not write loop part into a file, is that correct?