Magnetic properties of YbB12. Pressure effects.

For one of the famous and widely investigated intermediate valence compound YbB12, the experimental studies of the pressure effect on magnetic susceptibility χ (P) were carried out under helium gas pressure P up to 2 kbar at fixed temperatures 78 and 300 K using a pendulum type magnetometer. The measurements show a slight increase in susceptibility under pressure, which is consistent in sign with similar literature data for other ytterbium compounds with intermediate valence of Yb ions. Based on a model analysis of experimental data, the pressure derivative of Yb valence in YbB12 was estimated for the first time, the value of which is in line with the general trend of the valence behavior under pressure in rare earth compounds exhibiting intermediate valence. [ABSTRACT FROM AUTHOR]