How to assign value to angular material checkbox in angularjs

I am using anugular material checkbox in my application. I am facing problem in assigning the value to checkbox.

<div ng-repeat="rules in rulesList1.data.hits.hits">
    <md-checkbox md-no-ink aria-label="Checkbox No Ink" id="chkR1" ng-checked="rules._source.IsEnabled" class=" md-primary">
    </md-checkbox>
</div>

When I use this my checkbox become non-editable. I couldn't check or uncheck the box on using the above code. I dont know where I am going wrong.

Thanks in advance.