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Nickel samarium oxide (NiSmO₃), frequently referred to as samarium nickel oxide, is a synthetic mixed oxide with unusual thermo-optical properties. It and other nickel–rare earth oxides were prepared by Gérard Demazeau and co-workers at the University of Bordeaux (Talence, France) in 1971.

The crystalline oxides have typical ABX₃ perovskite structures (see image). Note that the nickel oxidation state is Ni(III).

In recent years, Mikhail A. Kats at the University of Wisconsin–Madison and colleagues there and at four other American research institutions discovered that NiSmO₃ , which holds that the energy radiated from a black body is related to the body’s absolute temperature. Specifically, j* = σT⁴, where

• j* is the total energy radiated per unit surface area of the body per unit time,
• σ is the Stefan–Boltzmann constant, and
• T is the absolute temperature of the body.

Constant σ is related to two other derived physical constants and the speed of light in a vacuum.

The emitted energy is manifested as electromagnetic radiation. In practical terms, as an object is heated, the radiated light becomes brighter. With many substances, including NiSmO₃, the radiation is infrared light. But Kats and co-workers found that the IR radiation from NiSmO₃ does not brighten with increasing temperature.

Does NiSmO₃ really violate the Stefan–Boltzmann law? Not really. As Emily Conover, physics writer for Science News, put it,

According to Kats and colleagues, NiSmO₃ is the first known material to exhibit temperature-independent thermal radiation. They state that this phenomenon “has substantial implications for infrared camouflage, privacy shielding, and radiative heat transfer.â€�