XML : '&' is not a valid value of the atomic type 'xs:Name'

whenever i am giving any special character to a variable, it throws below error. element Type: Schemas validity error : Element Type': '&' is not a valid value of the atomic type 'xs:Name'.

It accepts only colon (:).

Below is my schema.

  <element name="Type"                                 minOccurs="0" maxOccurs="unbounded">                          <complexType>                            <simpleContent>                              <extension base="Name">                                <attribute name="p"                                           type="positiveInteger" use="required"/>                              </extension>                            </simpleContent>                          </complexType>                        </element>    

Can anyone help me for finding from where this error is coming and how to get rid of it..