A magnetically-responsive thermal sensor determines the temperature of a local microscale volume and includes: a magnetic nano-thermometer that comprises a main magnetic layer and a subordinate magnetic layer disposed on the main magnetic layer, such that: the main magnetic layer comprises a first magnetic material that: couples, via magnetic coupling, with the subordinate magnetic layer; or has a large change in magnetization as a function of temperature that produces a magnetic phase transition of the main magnetic layer; and the subordinate magnetic layer comprises a second magnetic material that: couples, via magnetic coupling, with the main magnetic layer; or has a large change in magnetization as a function of temperature that produces a magnetic phase transition of the subordinate magnetic layer, wherein the magnetic nano-thermometer produces a magnetic response from which the temperature of the local microscale environment is determined.