Temperature, Wavelength, and Polarization Dependent Time Resolved Optical Spectroscopy of Half-Metallic CrO2

Published

May 1, 2005

Author(s)

H Huang, K A. Seu, A C. Reilly, Y Kadmon, William F. Egelhoff Jr.

Abstract

Chromium dioxide (CrO2) is an important transition metal oxide due to its half-metallic behavior. Recent investigation has measured a spin polarization at the Fermi surface of 0.96, which is the highest among all the discovered half-metals. Since CrO2 is metastable at 300 K in air and the surface decomposes spontaneously, difficulties arise in the experimental investigation of the electronic structure and dynamics in this material. The ultrafast laser pump-probe technique has proven to be a useful tool to elucidate such information in a variety of materials. We have performed temperature and wavelength dependent measurements of the transmitted pump-probe signal of epitaxial CrO2 thin films grown on rutile TiO2(110). Polarizations parallel and perpendicular to the crystal axis (c-axis) of the film were used, at wavelengths corresponding to important magnetic excitations: 1300nm (1eV), 800nm (1.5eV) and 650nm (2eV). Optical anisotropy is observed in the polarization-dependent pump probe measurements and is attributed to the electronic orbital anisotropy. Also, a critical change of transient transmission is observed at the Curie temperature of 386K. This behavior reveals the close relationship between the optical absorption and the spin dynamics of this material.

Citation

Journal of Applied Physics

Volume

97

Pub Type

Journals

Keywords

chromium dioxide, optical spectroscopy, time-resolved

Citation

Huang, H. , Seu, K. , Reilly, A. , Kadmon, Y. and Egelhoff Jr., W. (2005), Temperature, Wavelength, and Polarization Dependent Time Resolved Optical Spectroscopy of Half-Metallic CrO₂, Journal of Applied Physics (Accessed July 27, 2024)