Provided are: a magnetoresistance effect element that can be used as an element constituting a neural network, etc.; and a circuit device and circuit unit in which the magnetoresistance effect element is used. A write current pulse Pw1 from an upstream neuron circuit 51 is inputted to a first terminal T1 of a magnetoresistance effect element 53, and a write current pulse Pw2 from a downstream neuron circuit 52 is inputted to a second terminal T2. The write current pulses Pw1, Pw2 are outputted synchronously with a spike pulse when a neuron circuit is fired. A recording layer 12 is excited by energy with the write current by the preceding write current pulse. With the recording layer 12, the direction of the magnetization easily changes by excitation by energy, and the magnetization state changes with inversion of the magnetization direction of a portion of the recording layer 12 by a write current by a subsequent write current pulse. The magnetoresistance effect element 53 shows the same element resistance changes as the characteristics of asymmetrical type STDP.
MAGNETORESISTANCE EFFECT ELEMENT, CIRCUIT DEVICE, AND CIRCUIT UNIT