Thin-film magnetic head with heater in overcoat multilayer, head gimbal assembly with thin-film magnetic head, and magnetic disk drive apparatus with head gimbal assembly

A head gimbal assembly provided with a thin-film magnetic head comprising:

• a substrate;
• at least one magnetic head element formed on said substrate;
• an overcoat multilayer made up of a plurality of overcoat layers, formed on said substrate so as to cover said at least one magnetic head element;
• and
• at least one heating element to be heated at least during operation of said at least one magnetic head element,
• said at least one heating element provided in said overcoat multilayer,
• at least an overcoat layer located farthest from said substrate in said overcoat multilayer being formed on a flattened surface of another overcoat layer, and
• a coefficient of thermal expansion of said overcoat layer located farthest from said substrate in said overcoat multilayer being smaller than a coefficient of thermal expansion of an overcoat layer located closest to said substrate in said overcoat multilayer,
• said head gimbal assembly comprising:
• trace conductors for transmitting signals to/from said at least one magnetic head element of said thin-film magnetic head;
• lead wires for supplying currents to said at least one heating element of said thin-film magnetic head;
• and
• a support mechanism supporting said thin-film magnetic head.

A magnetic disk drive apparatus provided with at least one head gimbal assembly provided with a thin-film magnetic head comprising:

• a substrate;
• at least one magnetic head element formed on said substrate;
• an overcoat multilayer made up of a plurality of overcoat layers, formed on said substrate so as to cover said at least one magnetic head element;
• and
• at least one heating element to be heated at least during operation of said at least one magnetic head element,
• said at least one heating element provided in said overcoat multilayer,
• at least an overcoat layer located farthest from said substrate in said overcoat multilayer being formed on a flattened surface of another overcoat layer, and
• a coefficient of thermal expansion of said overcoat layer located farthest from said substrate in said overcoat multilayer being smaller than a coefficient of thermal expansion of an overcoat layer located closest to said substrate in said overcoat multilayer,
• said head gimbal assembly comprising:
• trace conductors for transmitting signals to/from said at least one magnetic head element of said thin-film magnetic head;
• lead wires for supplying currents to said at least one heating element of said thin-film magnetic head;
• and
• a support mechanism supporting said thin-film magnetic head,
• said magnetic disk drive apparatus comprising a current control means for controlling currents to be supplied to said at least one heating element.