SharePoint 2013 custom datetime column is not displaying in search result with keyword query language(KQL)

Mine is SharePoint 2013 onpremise environment.

I created a custom datetime field in custom list using object model.

Now I want to query that datetime field using SharePoint search keyword query language(KQL). So I have done a search full crawl in my environment and date time field crawled property got created after full crawl.

After that I have created a search managed property for datetime field by mapping the crawled property.

After creating managed property I have done search full crawl.

Now I am trying to search using keyword query language like DocumentDate:9/25/14 in search box but I am not getting any search result even I have a list item with that date value.

If any body has faced same issue and resolved it please help me here.

Avinash