Ab initio Studies of Structure and Magnetic Structure in YCo3H2.

We present an ab initio density functional study of magnetic phase transitions in the YCo3H2 system. The augmented plane wave and local orbital method as employed in the WIEN2K code is used to predict the structure and electronic structure of this compound. Comparison is made with recent X-ray diffraction and magnetization studies. The calculations suggest that the YCo3H2 system is ferrimagnetic in character. Further, fixed spin moment calculations are used to predict and interpret magnetic phase transitions observed in externally applied magnetic fields.