I believe name is a required property for radiobox. I did this and it seems to work.
var radioField = Ext.create('Ext.field.Radop', {
id: fieldName,
checked: true,
name:fieldName,
label: fieldName,
listeners: {
'uncheck': function(radio) {
console.log('destroy');
radio.destroy();
}
}
});
Ext.getCmp('QC23View').add(radioField);