Work

Shubnikov–de Haas oscillations in half-metallic ferromagnetic CrO 2 epitaxial films

Year: 2025

Type: article

Abstract: We present a study of the low-temperature, high-field magnetotransport behavior of epitaxially grown CrO 2 thin films on (100) TiO 2 substrates. Electron transport measurements confirm high sample quality, with a residual resistivity ratio as large as 45. A logarithmic fit of the low-temperature regime yields a T 4.5 power law, indicative of the elusive double-magnon scattering in half-metallic ferromagnets. Angle-dependent anisotropic magnetoresistance (AMR) measurements reveal a large projected density of states along [001] with a maximum AMR value of 2.4%. Pronounced, axis-dependent Shubnikov–de Haas (SdH) oscillations are observed in the longitudinal magnetoresistance (MR), with discrete Landau levels mapped at various tilt angles of the magnetic field. Their angular dependence follows a 1 / cos θ relation pointing to a highly anisotropic Fermi surface, and amplitude scaling adheres closely to the thermodynamic Lifshitz-Kosevich formalism. The out-of-plane MR reaches 6.58%, the largest reported for CrO 2 thin films. Notably, this study presents an observation of SdH oscillations in a half-metallic oxide with near-perfect spin polarization, a significant advancement in the field of spintronics.

Source: Physical review. B./Physical review. B

DOI: 10.1103/v73x-5ptd