How can I write to external removable sdcard in Android

I write files using these following directory accesses. But all files are written inside the phone memory.

None of the files is written inside external sd card.

File.applicationStorageDirectory

     /data/data/<applicationID>/<filename>/Local Store

File.desktopDirectory

     /mnt/sdcard

File.documentsDirectory

     /mnt/sdcard

File.userDirectory

     /mnt/sdcard