Is reward (promotion or increment) mandatory after Performance Evaluation?

There is a logical fallacy in the question.  It's an evaluation: the whole point is that you don't know what the consequences may be.

being loyal to a company and company not appreciating that, will only demotivate the employee than making him work better for better future.

By the way you mean here after the evaluation what should have to do to the employee ?

 That what i get ,If i suggest is true my answering ( After evaluation ) we should try to improve spirit to all employees and we not say any promises we can't achieve .   Hope my answering useful 

and Thanks for invite me to answering   

Have nice day

Thanks for invitation,

Of course, as long as objectives are achieved.

it is not mandatory after Performance Evaluation you get rewarded or promoted

most of companies pay top  performance Staff an  increment or promotion but not everyone receive

I believe that your question about regular increments? or when employee get promotion during his service?

Yes. There is no second thought about it. When the employee performs well and meet/exceed the expectations set by the company, they should be properly rewarded. Rewards can be anything which is monetary benefits or non monetary benefits which motivates the employee to contribute more in the coming years.

In my previous experiences while handling teams, i see sudden fall of commitment from the team members which made us organize several meetings to bring up their contribution.

Being in service industry, employees are the greatest assets.

If it was mandatory - then why do the whole evaluation exercise? Hence, it's not mandatory and depends on a lot of related factors apart from a Superior Performance Score of an employee - like performance of the business in that period, agreed bottom line, available budget for increments/ bonuses, etc. 

agree with all great answer above