Can you sue an employer for defamation for a intentionally false, negative employment reference.?

I applied for a job a little over a month ago in which I am more than qualified for. My interview was great, so much so, that I was told I would definantly be hearing back from the company. After calling my current employer, who does not like me, I was informed I did not get the job based upon a refernece from the aforementioned current employer. This baffles me because I always come in early, stay late, come in on my off days, work hard, provide excellent service, am polite, have never been wirtten up, and as a matter of fact I have trained multiple new employees with great success. I even get compliments from my managers, manager for how well and hard I work. I'm sure because we are short staffed, she might not want to loose another employee but can she really get away with giving me a unfounded and false negative employment reference? If not, what can I do about this?