first store the values in $rootScope as
.run(function($rootScope){
$rootScope.myData = {name : "nikhil"}
})
.controller('myCtrl', function($scope) {
var a ="Nikhilesh";
$scope.myData.name = a;
});
.controller('myCtrl2', function($scope) {
var b = $scope.myData.name;
)}
$rootScope is the parent of all $scope, each $scope receives a copy of $rootScope data which you can access using $scope itself.