Ferromagnetism in Pd(100) Ultrathin Films Enhanced by Distortion

A significant distortion of crystal structure was observed in Pd(100) ultrathin film deposited on a SrTiO3 substrate that shows ferromagnetism induced by quantum-well states. An in-situ X-ray crystal truncation rod scattering measurement showed an expansion of the lattice in the ferromagnetic Pd(100) ultrathin film with a thickness of 3.19 nm. This result explains the previous observation that the measured ferromagnetic magnetization in Pd(100) is much larger than that predicted by the calculation.