arXiv subjects

Takashi Yamasaki

Publications and source records attributed to Takashi Yamasaki.

2 recordsLinked to original sources

arXiv2008

Room Temperature Ferromagnetic Semiconductor Rutile Ti1-xCoxO2-δEpitaxial Thin Films Grown by Sputtering Method

Room temperature ferromagnetic semiconductor rutile Ti1-xCoxO2-δ(101) epitaxial thin films were grown on r-sapphire substrates by a dc sputtering method. Ferromagnetic magnetization, magnetic circular dichroism, and anomalous Hall effect were clearly observed at room temperature in sputter-grown films for the first time. The magnetization value is nearly as large as 3μB/Co that is consistent with the high spin state Co2+ in this compound recently established by spectroscopic methods. Consequently, its originally large magneto-optical response is further enhanced.

cond-mat.mtrl-sci↗

arXiv2007

A scaling relation of anomalous Hall effect in ferromagnetic semiconductors and metals

A scaling relation of the anomalous Hall effect recently found in a ferromagnetic semiconductor (Ti,Co)O_2_ is compared with those of various ferromagnetic semiconductors and metals. Many of these compounds with relatively low conductivity sigma_xx_ < 10^4 ohm^-1 cm^-1 are also found to exhibit similar relation: anomalous Hall conductivity sigma_AH_ approximately scales as sigma_AH_ proportional to sigma_xx_^1.6, that is coincident with a recent theory. This relation is valid over five decades of sigma_xx_ irrespective of metallic or hopping conduction.

cond-mat.mtrl-sci↗