The word is actually spelled "Djinn". In Islamic belief they are spiritual beings that can be either good or evil. You can read quite a bit about them at http://paranormal.about.com/od/demonsandexorcism/a/aa060506.htm
As Lark stated Djinn are considered beings of free will and like humans can be either good or evil based on their choices. I have not done any indepth research but I have never heard of the term devil Djinn. If you believe in the religious based aspect of Djinn the Quran calls Djinn beings of smoke & fire that were created prior to humans and rebelled because they were told to essentially consider us better than them. To be precise I believe the text is said to mention they were told to bow to us, but it has been a while since I looked into it. There are different Djinn titles that are said to refer to their strength & temperament, but the term devil djinn is not one of these title.
The jinns are creatures just like us that is what the quran says,they did not rebell against any body.it was satan who rebel against his God by refusing to bow before adam.this what the qurans says so (satan is to you an open enemy)
My friend johnas claims that Djinn are loving beings and helpful. He says they are all around the world. He told me the term "devil djinn" is what Ifrit and Jaal Djinn are.
He says their are four races of them Marid,Shaitan,Jaal and Ifirt.
Maried are highest and holiest and most powerful of all Djinn.
Shaitan are the weakest but very wise and kind. Johnas's says Shaitan reminds him of Buddhist monks.
Jaal are evil,they are most like humans,in body,they are weak. But for fun they will make a human get cancer or another diseases.
Ifirt are the second most powerful,but are the most evil of all Djinn. They love to cause humans harm. They see humans as low beings and should be dead.
Johnas told me that most everying known about Djinn is false,the only way to know the truth is to ask a Maried Djinn.
What was told to Johnas,by his own Djinn about the Qu'ran, is almost everything in it about Djinn is false. The only few prayers that will get rid of a Djinn is a Buddhist mantra. 'Om Ma Ni Pad Me Hum" must be chanted 108 times.
The Ifirt Djinn names can be spelled like,"Ifirt" "ifrit"
The Jaal Djinn names can be spelled like "Jaal" Gaaal" "Ghul" "Ghule" "Jann" "Jaan", they are many names for Jaal Djinn.