<p dir="ltr">The market for infrared detectors has grown significantly in recent years due to the wide variety of applications from astronomy to medical thermography. Additionally, several emerging applications for high-speed infrared technologies are in development such as infrared LIDAR, autonomous vehicles, semiconductor device analysis, and free space communication. Improvements in the readout-speed and sensitivity of uncooled infrared detectors are required for some of these applications, and have been a long-standing goal in the field. Two technologies currently dominate the detection of infrared radiation, photodiodes and bolometers. Bolometers are extremely interesting as they are currently the most sensitive infrared detectors (either cooled or uncooled). We will propose and demonstrate a new type of bolometric infrared detector based on a highly structured spintronic material. The device's detection mechanism utilizes thermally activated magnetic transitions in a nanoscale magnetic device. We will also discuss a classification for detectors based on their digital-mode (discrete) or analog (continuous) readout signals. We develop a stochastic model to compare the sensitivity of these detectors. From this model we demonstrate several fundamental limits in the measurement of temperature by infrared detection.</p>